Method, apparatus and system for transmitting and receiving control channel of wireless communication system

ABSTRACT

The present invention relates to a wireless communication system. In particular, the present invention relates to a method including: receiving configuration information on a periodic signal through a higher layer signal, wherein a transmission/reception position of the periodic signal is configured to a first set of symbols within each slot which is set periodically; monitoring a PDCCH associated with a slot configuration of a first slot in order to receive slot configuration information for the first slot in which the transmission/reception position of the periodic signal is present; and performing a process for transmitting/receiving the periodic signal in the first slot, wherein when the first set of symbols within the first slot is designated as a flexible symbol by a higher layer, a transmission/reception of the periodic signal in the first slot is selectively performed according to a detection result of the PDCCH, and wherein the flexible symbol means a symbol whose purpose can be re-designated to DL, UL or flexible according to the slot configuration information of the PDCCH, and an apparatus therefor.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method and apparatus for transmitting andreceiving control channels in a wireless communication system supportingtime division multiple access.

BACKGROUND ART

The 3rd generation partnership project new radio (3GPP NR) systemimproves the spectral efficiency of the network, enabling operators toprovide more data and voice services over a given bandwidth. As aresult, the 3GPP NR system is designed to meet the demands forhigh-speed data and media transmissions in addition to supporting largevolumes of voice. The advantages of the NR system are supports of highprocessing amount, low latency, frequency division duplex (FDD) and timedivision duplex (TDD) on the same platform, improved end userexperience, and a simple architecture with low operating costs.

For more efficient data processing, a Dynamic TDD of the NR system mayuse a method of varying the number of orthogonal frequency divisionmultiplexing (OFDM) symbols that can be used for uplink/downlinkaccording to data traffic directions of users of a cell. For example,the base station may allocate a plurality of downlink OFDM symbols to aslot (or subframe) when a downlink traffic of the cell is larger than anuplink traffic. The information on the slot configuration should betransmitted to the terminals.

DISCLOSURE Technical Problem

An object of the present invention is to provide a method for informinga terminal of information on a slot configuration, a communicationmethod according to the slot configuration, and an apparatus therefor.

Technical objects desired to be achieved in the present invention arenot limited to the aforementioned objects, and other technical objectsnot described above will be clearly understood by those skilled in theart from the following disclosure.

Technical Solution

A first aspect of the present invention provides a method fordetermining a reception of a downlink signal by a user equipment in awireless communication system, the method including: receivingconfiguration information on a periodic signal through a higher layersignal, wherein a reception position of the periodic signal isconfigured to a first set of symbols within each slot which is setperiodically; monitoring a physical downlink control channel (PDCCH)associated with a slot configuration of a first slot in order to receiveslot configuration information for the first slot in which the receptionposition of the periodic signal is present; and performing a process forreceiving the periodic signal in the first slot, wherein when the firstset of symbols within the first slot is designated as a flexible symbolby a higher layer, a reception of the periodic signal in the first slotis selectively performed according to a detection result of the PDCCH,and wherein the flexible symbol means a symbol whose purpose can bere-designated to downlink (DL), uplink (UL) or flexible according to theslot configuration information of the PDCCH.

A second aspect of the present invention provides a user equipment usedfor a wireless communication system, the user equipment including: acommunication module; and a processor, wherein the processor receivesconfiguration information on a periodic signal through a higher layersignal, wherein a reception position of the periodic signal isconfigured to a first set of symbols within each slot which is setperiodically, monitors a physical downlink control channel (PDCCH)associated with a slot configuration of a first slot in order to receiveslot configuration information for the first slot in which the receptionposition of the periodic signal is present, and performs a process forreceiving the periodic signal in the first slot, wherein when the firstset of symbols within the first slot is designated as a flexible symbolby a higher layer, a reception of the periodic signal in the first slotis selectively performed according to a detection result of the PDCCH,and wherein the flexible symbol means a symbol whose purpose can bere-designated to downlink (DL), uplink (UL) or flexible according to theslot configuration information of the PDCCH.

In the first and second aspects, the periodic signal may include achannel status information reference signal (CSI-RS).

In the first and second aspects, the PDCCH may include a group common(GC)-PDCCH having a slot configuration for the first slot, and when thefirst set of symbols within the first slot is designated as a flexiblesymbol by the higher layer and the GC-PDCCH is not detected, thereception of the periodic signal in the first slot may be skipped.

In the first and second aspects, the PDCCH may include a group common(GC)-PDCCH having slot configuration information for the first slot, andwhen the first set of symbols within the first slot is designated as aflexible symbol by the higher layer and the slot configurationinformation detected from the GC-PDCCH indicates the first set ofsymbols as flexible, the reception of the periodic signal in the firstslot may be skipped.

In the first and second aspects, the reception of the periodic signal inthe first slot may be performed only when the slot configurationinformation detected from the GC-PDCCH indicates the first set ofsymbols as a DL symbol.

In the first and second aspects, the PDCCH may include a user specific(US)-PDCCH having downlink scheduling information, and when the firstset of symbols within the first slot is designated as a flexible symbolby the higher layer and a DL signal is scheduled for the first set ofsymbols by the US-PDCCH, the reception of the periodic signal in thefirst slot may be performed.

A third aspect of the present invention provides a method fordetermining a transmission of an uplink signal by a user equipment in awireless communication system, the method including: receivingconfiguration information on a periodic signal through a higher layersignal, wherein a transmission position of the periodic signal isconfigured to a first set of symbols within each slot which is setperiodically; monitoring a physical downlink control channel (PDCCH)associated with a slot configuration of a first slot in order to receiveslot configuration information for the first slot in which thetransmission position of the periodic signal is present; and performinga process for transmitting the periodic signal in the first slot,wherein when the first set of symbols within the first slot isdesignated as a flexible symbol by a higher layer, a transmission of theperiodic signal in the first slot is selectively performed according toa detection result of the PDCCH, and wherein the flexible symbol means asymbol whose purpose can be re-designated to downlink (DL), uplink (UL)or flexible according to the slot configuration information of thePDCCH.

A fourth aspect of the present invention provides a user equipment usedfor a wireless communication system, the user equipment including: acommunication module; and a processor, wherein the processor receivesconfiguration information on a periodic signal through a higher layersignal, wherein a transmission position of the periodic signal isconfigured to a first set of symbols within each slot which is setperiodically, monitors a physical downlink control channel (PDCCH)associated with a slot configuration of a first slot in order to receiveslot configuration information for the first slot in which thetransmission position of the periodic signal is present, and performs aprocess for transmitting the periodic signal in the first slot, whereinwhen the first set of symbols within the first slot is designated as aflexible symbol by a higher layer, a transmission of the periodic signalin the first slot is selectively performed according to a detectionresult of the PDCCH, and wherein the flexible symbol means a symbolwhose purpose can be re-designated to downlink (DL), uplink (UL) orflexible according to the slot configuration information of the PDCCH.

In the third and fourth aspects, the periodic signal may include asounding reference signal (SRS).

In the third and fourth aspects, the PDCCH may include a group common(GC)-PDCCH having a slot configuration for the first slot, and when thefirst set of symbols within the first slot is designated as a flexiblesymbol by the higher layer and the GC-PDCCH is not detected, thetransmission of the periodic signal in the first slot may be skipped.

In the third and fourth aspects, the PDCCH may include a group common(GC)-PDCCH having slot configuration information for the first slot, andwhen the first set of symbols within the first slot is designated as aflexible symbol by the higher layer and the slot configurationinformation detected from the GC-PDCCH indicates the first set ofsymbols as flexible, the transmission of the periodic signal in thefirst slot may be skipped.

In the third and fourth aspects, the transmission of the periodic signalin the first slot may be performed only when the slot configurationinformation detected from the GC-PDCCH indicates the first set ofsymbols as a DL symbol.

In the third and fourth aspects, the PDCCH may include a user specific(US)-PDCCH having uplink scheduling information, and when the first setof symbols within the first slot is designated as a flexible symbol bythe higher layer and a DL signal is scheduled for the first set ofsymbols by the US-PDCCH, the transmission of the periodic signal in thefirst slot may be performed.

Advantageous Effects

According to exemplary embodiments of the present invention, informationon the slot configuration can be efficiently informed to the terminal,and the signals can be efficiently transmitted and received between thebase station and the terminal according to the slot configuration.

Effects to be acquired in the present invention are not limited to theaforementioned effects, and other effects not described above will beclearly understood by those skilled in the art from the followingdisclosure.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example of a wireless frame structure used in awireless communication system.

FIG. 2 illustrates an example of a downlink (DL)/uplink (UL) slotstructure in a wireless communication system.

FIG. 3 is a diagram illustrating a physical channel used in a 3GPPsystem and a general signal transmission method using the physicalchannel.

FIG. 4 illustrates an SS/PBCH block for initial cell access in a 3GPP NRsystem.

FIG. 5(a) is a diagram of a procedure for transmitting controlinformation in a 3GPP NR system.

FIG. 5(b) is a diagram illustrating CCE aggregation of PDCCH andmultiplexing of PDCCH.

FIG. 6 is a diagram illustrating a control resource set (CORESET) inwhich a physical downlink control channel (PDCCH) can be transmitted ina 3GPP NR system.

FIG. 7 is a diagram illustrating CCE aggregation search space allocationfor a common search space and a UE specific (or terminal specific)search space.

FIG. 8 is a conceptual diagram illustrating carrier aggregation.

FIG. 9 is a diagram for describing single carrier communication andmulticarrier communication.

FIG. 10 is a diagram illustrating an example in which a cross carrierscheduling technique is applied.

FIG. 11 is a diagram illustrating a slot configuration possible in atime division multiple access.

FIG. 12 is a diagram illustrating a slot configuration possible in atime division multiple access.

FIG. 13 illustrates indicating multiple slot configuration through agroup common (GC) PDCCH in a time division multiple access.

FIG. 14 is a block diagram illustrating a configuration of slotsscheduling in a UE-specific PDCCH carrying scheduling information in atime division multiple access.

FIG. 15 illustrates that a user scheduled as DL-only according to anembodiment of the present invention identifies a slot configurationusing a group common PDCCH of a scheduled slot in order to confirmwhether the next slot is UL-only.

FIG. 16 illustrates that a user scheduled as DL-only according to anembodiment of the present invention identifies a slot configurationusing a previous group common PDCCH closest to the scheduled slot inorder to confirm whether the next slot is UL-only.

FIG. 17 illustrates that a user scheduled as UL-only according to anembodiment of the present invention identifies a slot configurationusing a group common PDCCH of a previous slot of the scheduled slot inorder to confirm whether the previous slot is DL-only.

FIG. 18 illustrates that a user scheduled as UL-only according to anembodiment of the present invention identifies a slot configurationusing a previous group common PDCCH closest to the scheduled slot inorder to confirm whether the previous slot is DL-only.

FIG. 19 illustrates a slot configuration determination of a scheduledUE.

FIG. 20 is a block diagram illustrating of identifying a scheduled slotstructure using a group common PDCCH of the scheduled slot in the caseof cross slot scheduling according to an embodiment of the presentinvention.

FIG. 21 is a block diagram illustrating of identifying a scheduled slotstructure using a previous group common PDCCH closest to the scheduledslot in case of cross slot scheduling according to an embodiment of thepresent invention.

FIG. 22 illustrates a slot configuration determination when a UE thatperiodically transmits and receives a signal does not have schedulinginformation.

FIG. 23 illustrates a slot configuration determination when a UE thatperiodically transmits and receives a signal has scheduling information.

FIG. 24 is a block diagram illustrating a procedure of obtaining slotconfiguration information according to an embodiment of the presentinvention.

FIG. 25 is a block diagram illustrating a procedure for receiving aPDCCH including slot configuration information according to anembodiment of the present invention.

FIG. 26 is a diagram illustrating a case where a base station and a userequipment use different slot configurations in a time division multipleaccess.

FIG. 27 illustrates changing a CORESET for monitoring a group commonPDCCH according to an embodiment of the present invention.

FIG. 28 is a block diagram illustrating configurations of a userequipment and a base station, respectively, according to an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Terms used in the specification adopt general terms which are currentlywidely used as possible by considering functions in the presentinvention, but the terms may be changed depending on an intention ofthose skilled in the art, customs, and emergence of new technology.Further, in a specific case, there is a term arbitrarily selected by anapplicant and in this case, a meaning thereof will be described in acorresponding description part of the invention. Accordingly, it intendsto be revealed that a term used in the specification should be analyzedbased on not just a name of the term but a substantial meaning of theterm and contents throughout the specification.

Throughout this specification and the claims that follow, when it isdescribed that an element is “connected” to another element, the elementmay be “directly connected” to the other element or “electricallyconnected” to the other element through a third element. Further, unlessexplicitly described to the contrary, the word “comprise” will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements unless otherwise stated. Moreover,limitations such as “more than or equal to” or “less than or equal to”based on a specific threshold may be appropriately substituted with“more than” or “less than”, respectively, in some exemplary embodiments.

The following technology may be used in various wireless access systems,such as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier-FDMA(SC-FDMA), and the like. The CDMA may be implemented by a wirelesstechnology such as universal terrestrial radio access (UTRA) orCDMA2000. The TDMA may be implemented by a wireless technology such asglobal system for mobile communications (GSM)/general packet radioservice (GPRS)/enhanced data rates for GSM evolution (EDGE). The OFDMAmay be implemented by a wireless technology such as IEEE 802.11 (Wi-Fi),IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like.The UTRA is a part of a universal mobile telecommunication system(UMTS). 3^(rd) generation partnership project (3GPP) long term evolution(LTE) is a part of an evolved UMTS (E-UMTS) using evolved-UMTSterrestrial radio access (E-UTRA) and LTE-advanced (A) is an evolvedversion of the 3GPP LTE. 3GPP new radio (NR) is a system designedseparately from LTE/LTE-A, and is a system for supporting enhancedmobile broadband (eMBB), ultra-reliable and low latency communication(URLLC), and massive machine type communication (mMTC) services, whichare requirements of IMT-2020. For the clear description, 3GPP NR ismainly described, but the technical idea of the present invention is notlimited thereto.

Unless otherwise specified in this specification, a base station mayrefer to a next generation node B (gNB) as defined in 3GPP NR.Furthermore, unless otherwise specified, a terminal may refer to a userequipment (UE).

FIG. 1 illustrates an example of a wireless frame structure used in awireless communication system.

Referring to FIG. 1 , the wireless frame (or radio frame) used in the3GPP NR system may have a length of 10 ms (Δf_(max)N_(f)/100)*T_(c)). Inaddition, the wireless frame includes 10 subframes (SFs) having equalsizes. Herein, Δf_(max)=480*10³ Hz, N_(f)=4096,T_(c)=1/(Δf_(ref)*N_(f,ref)), Δf_(ref)=15*10³ Hz, and N_(f,ref)=2048.Numbers from 0 to 9 may be respectively allocated to 10 subframes withinone wireless frame. Each subframe has a length of 1 ms and may includeone or more slots according to a subcarrier spacing. More specifically,in the 3GPP NR system, the subcarrier spacing that may be used is15*2^(μ) kHz, and μ can have a value of μ=0, 1, 2, 3, 4 as subcarrierspacing configuration. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz and 240kHz may be used for subcarrier spacing. One subframe having a length of1 ms may include 2^(μ) slots. In this case, the length of each slot is2^(−μ) ms. Numbers from 0 to 2^(μ)-1 may be respectively allocated to2^(μ) slots within one subframe. In addition, numbers from 0 to10*2^(μ)-1 may be respectively allocated to slots within one subframe.The time resource may be distinguished by at least one of a wirelessframe number (also referred to as a wireless frame index), a subframenumber (also referred to as a subframe number), and a slot number (or aslot index).

FIG. 2 illustrates an example of a downlink (DL)/uplink (UL) slotstructure in a wireless communication system. In particular, FIG. 2shows the structure of the resource grid of the 3GPP NR system.

There is one resource grid per antenna port. Referring to FIG. 2 , aslot includes a plurality of OFDM symbols in a time domain and includesa plurality of resource blocks (RBs) in a frequency domain. An OFDMsymbol also means one symbol duration. Unless otherwise specified, anOFDM symbol may be simply referred to as a symbol. Referring to FIG. 2 ,a signal transmitted in each slot may be represented by a resource gridconsisting of N^(size,μ) _(grid, x)*N^(RB) _(sc) subcarriers, andN^(slot) _(symb) OFDM symbols. Here, x=DL for the downlink resourcegrid, and x=UL for the uplink resource grid. N^(size,μhd grid, x)denotes the number of resource blocks (downlink or uplink according tox) according to a subcarrier spacing configuration μ, and N^(slot)_(symb) denotes the number of OFDM symbols in a slot. N^(RB) _(sc) isthe number of subcarriers constituting one RB and N^(RB) _(sc)=12. AnOFDM symbol may be referred to as a cyclic shift OFDM (CP-OFDM) symbolor a discrete Fourier transform spreading OFDM (DFT-s-OFDM) symbolaccording to a multiple access scheme. The number of OFDM symbolsincluded in one slot may vary according to the length of a cyclic prefix(CP). For example, in the case of a normal CP, one slot includes 14 OFDMsymbols, but in the case of an extended CP, one slot may include 12 OFDMsymbols. In a specific embodiment, the extended CP may only be used at60 kHz subcarrier spacing. In FIG. 2 , for convenience of description,one slot includes 14 OFDM symbols by way of example, but embodiments ofthe present invention may be applied in a similar manner to a slothaving a different number of OFDM symbols. Referring to FIG. 2 , eachOFDM symbol includes N^(size,μ) _(grid, x)*N^(RB) _(sc) subcarriers inthe frequency domain. The type of subcarrier may be divided into a datasubcarrier for data transmission, a reference signal subcarrier fortransmission of a reference signal, and a guard band. The carrierfrequency is also referred to as the center frequency (fc).

An RB may be defined by N^(slot) _(symb) (e.g., 14) consecutive OFDMsymbols in the time domain and may be defined by N^(RB) _(sc) (e.g., 12)consecutive subcarriers in the frequency domain. As a reference, aresource including one OFDM symbol and one subcarrier may be referred toas a resource element (RE) or a tone. Therefore, one RB may includeN^(slot) _(symb)*N^(RB) _(sc) resource elements. Each resource elementin the resource grid may be uniquely defined by a pair of indexes (k, l)in one slot. k may be an index numbered from 0 to N_(size,μ)_(grid,x)*N^(RB) _(sc)−1 in the frequency domain, and l may be an indexnumbered from 0 to N^(slot) _(symb)−1 in the time domain.

On the other hand, one RB may be mapped to one physical resource block(PRB) and one virtual resource block (VRB). The PRB may be defined byN^(slot) _(symb) (e.g., 14) consecutive OFDM symbols in the time domain.Further, the PRB may be defined by N^(RB) _(sc) (e.g., 12) consecutivesubcarriers in the frequency domain. Therefore, one PRB may includeN^(RB) _(sc)*N^(slot) _(symb) resource elements.

In order for the user equipment to receive a signal from the basestation or to transmit a signal to the base station, the time/frequencysynchronization of the user equipment may be synchronized with thetime/frequency synchronization of the base station. This is because thebase station and the user equipment need to be synchronized, so thatuser equipment can determine the time and frequency parameters requiredfor demodulating the DL signal and transmitting the UL signal at thecorrect time.

FIG. 3 is a diagram for explaining a physical channel used in a 3GPPsystem (e.g., NR) and a general signal transmission method using thephysical channel. When the power of the user equipment is turned on orthe user equipment enters a new cell, the user equipment performs aninitial cell search (S301). Specifically, the user equipment maysynchronize with the base station in the initial cell search. For this,the user equipment may receive a Primary Synchronization Signal (PSS)and a Secondary Synchronization Signal (SSS) from a base station,synchronize with the base station, and obtain information such as a cellID. Thereafter, the user equipment may receive the physical broadcastchannel from the base station and obtain the in-cell broadcastinformation. Upon completion of the initial cell search, the userequipment receives a Physical Downlink Control Channel (PDCCH) and aPhysical Downlink Shared Channel (PDSCH) according to informationcarried in the PDCCH, so that the user equipment can obtain morespecific system information than the system information obtained throughthe initial cell search (S302). When the user equipment initiallyaccesses the base station or does not have radio resources for signaltransmission, the user equipment may perform a random access procedureon the base station (S303 to S306). For this, the user equipment maytransmit a specific sequence as a preamble through a Physical RandomAccess Channel (PRACH) (S303 and S305) and receive a response messagefor the preamble on the PDCCH and the corresponding PDSCH from the basestation (S304 and S306). In case of the contention-based RACH, acontention resolution procedure may be additionally performed. After theabove-described procedure, the user equipment receives PDCCH/PDSCH(S307) and transmits a Physical Uplink Shared Channel (PUSCH)/PhysicalUplink Control Channel (PUCCH) (S308) as a general phase/DL signaltransmission procedure. In particular, the user equipment may receive DLControl Information (DCI) through the PDCCH. The DCI may include controlinformation such as resource allocation information for the userequipment. Also, the format of the DCI may vary depending on theintended use of the DCI. The control information that the user equipmenttransmits to or receives from the base station through the UL includes aDL/UL ACK/NACK signal, a Channel Quality Indicator (CQI), a PrecodingMatrix Index (PMI), a Rank Indicator (RI). In the 3GPP NR system, theuser equipment may transmit control information such as HARQ-ACK and CSIdescribed above through the PUSCH and/or PUCCH.

FIG. 4 illustrates an SS/PBCH block for initial cell access in a 3GPP NRsystem.

When the power of the user equipment is turned on and the user equipmenttries to access a new cell, the user equipment may obtain time andfrequency synchronization with the cell and perform an initial cellsearch procedure. The user equipment can detect the physical cellidentity N^(cell) _(ID) of the cell in the initial cell searchprocedure. For this, the user equipment may receive a synchronizationsignal, for example, a PSS and an SSS from a base station andsynchronize with the base station. In this case, the user equipment mayobtain information such as a cell identity (ID). Referring to FIG. 4(a),a synchronization signal will be described in more detail. Thesynchronization signal may be divided into PSS and SSS. The PSS may beused to obtain time domain synchronization and/or frequency domainsynchronization, such as OFDM symbol synchronization and slotsynchronization. The SSS may be used to obtain frame synchronization andcell group ID. Referring to FIG. 4(a) and Table 1, the SS/PBCH blockconsists of 20 RBs (=240 subcarriers) in the frequency axis, andconsists of 4 OFDM symbols in the time axis. Here, in the SS/PBCH block,PSS in the first OFDM symbol and SSS in the third OFDM symbol aretransmitted in 56, 57, . . . , 182 subcarriers. Here, the lowestsubcarrier index of the SS/PBCH block is numbered from 0. In the firstOFDM symbol in which the PSS is transmitted, the base station does nottransmit a signal in the remaining subcarriers, that is, 0, 1, . . . ,55, 183, 184, . . . , 239 subcarriers. In the third OFDM symbol in whichthe SSS is transmitted, the base station does not transmit a signal in48, 49, . . . , 55, 183, 184, . . . , 191 subcarriers. In the SS/PBCHblock, the base station transmits the PBCH signal through the remainingRE except the above signal.

TABLE 1 Channel OFDM symbol number/relative to Subcarrier number k orsignal the start of an SS/PBCH block relative to the start of an SS/PBCHblock PSS 0 56, 57, . . . , 182 SSS 2 56, 57, . . . , 182 Set to 0 0 0,1, . . . , 55, 183, 184, . . . , 239 2 48, 49, . . . , 55, 183, 184, . .. , 191 1, 3 0, 1, . . . , 239 PBCH 2 0, 1, . . . , 47, 192, 193, . . ., 239 DM-RS for 1, 3 0 + v, 4 + v, 8 + v, . . . , 236 + v PBCH 2 0 + v,4 + v, 8 + v, . . . , 44 + v 192 + v, 196 + v, . . . , 236 + v

The SS may represent a total of 1008 unique physical layer cell IDsthrough a combination of 3 PSSs and 336 SSs. Specifically, the physicallayer cell ID is grouped into 336 physical-layer cell-identifier groups,where each group includes 3 unique identifiers such that eachphysical-layer cell ID is part of only one physical-layercell-identifier group. Therefore, the physical layer cell identifierN^(cell) _(ID)=3N⁽¹⁾ _(ID)+N⁽²⁾ _(ID) may be defined by a number N⁽¹⁾_(ID) ranging from 0 to 335 indicating a physical-layer cell-identifiergroup and a number N⁽²⁾ _(ID) ranging from 0 to 2 indicating aphysical-layer identifier in the physical-layer cell-identifier group.The user equipment may detect the PSS and identify one of the threeunique physical-layer identifiers. In addition, the user equipment maydetect the SSS and identify one of the 336 physical layer cell IDsassociated with the physical-layer identifier. The PSS signal is asfollows.

d _(PSS)(n)=1−2x(m)

m=(n+43N ⁽²⁾ _(ID))mod 127

0≤n<127

x(i+7)=(x(i+4)+x(i))mod 2

Here, and

[x(6) x(5) x(4) x(3) x(2) x(1) x(0)]=[1 1 1 0 1 1 0] SSS is as follows.

d_(SSS)(n) = [1 − 2x₀((n + m₀)mod127)][1 − 2x₁((n + m₁)mod127)]$m_{0} = {{15\left\lfloor \frac{N_{ID}^{(1)}}{112} \right\rfloor} + {5N_{ID}^{(2)}}}$m₁ = N_(ID)⁽¹⁾mod112 0 ≤ n < 127 ${Here},{\begin{matrix}{{x_{0}\left( {i + 7} \right)} = {\left( {{x_{0}\left( {i + 4} \right)} + {x_{0}(i)}} \right){mod}2}} \\{{x_{1}\left( {i + 7} \right)} = {\left( {{x_{1}\left( {i + 1} \right)} + {x_{1}(i)}} \right){mod}2}}\end{matrix}{and}}$ $\begin{matrix}\left. \begin{matrix}\left\lbrack {x_{0}(6)} \right. & {x_{0}(5)} & {x_{0}(4)} & {x_{0}(3)} & {x_{0}(2)} & {x_{0}(1)} & {\left. {x_{0}(0)} \right\rbrack = \left\lbrack \begin{matrix}0 & 0 & 0 & 0 & 0 & 0 & 1\end{matrix} \right.}\end{matrix} \right\rbrack \\\left. \begin{matrix}\left\lbrack {x_{1}(6)} \right. & {x_{1}(5)} & {x_{1}(4)} & {x_{1}(3)} & {x_{1}(2)} & {x_{01}(1)} & {\left. {x_{1}(0)} \right\rbrack = \left\lbrack \begin{matrix}0 & 0 & 0 & 0 & 0 & 0 & 1\end{matrix} \right.}\end{matrix} \right\rbrack\end{matrix}.$

A wireless frame with a 10 ms duration may be divided into two halfframes with a duration of 5 ms. Referring to FIG. 4(b), a descriptionwill be made of a slot in which SS/PBCH blocks are transmitted in eachhalf frame. A slot in which the SS/PBCH block is transmitted may be anyone of the cases A, B, C, D, and E. In the case A, the subcarrierspacing is 15 kHz and the starting time point of the SS/PBCH block is{2, 8}+14*n symbols. In this case, n=0, 1 at a carrier frequency of 3GHz or less. At frequencies below 6 GHz above 3 GHz, n=0, 1, 2, or 3. Inthe case B, the subcarrier spacing is 30 kHz and the starting time pointof the SS/PBCH block is {4, 8, 16, 20}+28*n. In this case, n=0, 1 at acarrier frequency of 3 GHz or less. At frequencies below 6 GHz above 3GHz, n=0 or 1. In the case C, the subcarrier spacing is 30 kHz and thestarting time point of the SS/PBCH block is {2, 8}+14*n. In this case,n=0 or 1 at a carrier frequency of 3 GHz or less. At frequencies below 6GHz above 3 GHz, n=0, 1, 2, or 3. In the case D, the subcarrier spacingis 120 kHz and the starting time point of the SS/PBCH block is {4, 8,16, 20}+28*n. In this case, at a carrier frequency of 6 GHz or more,n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, or 18. In the caseE, the subcarrier spacing is 240 kHz and the starting time point of theSS/PBCH block is {8, 12, 16, 20, 32, 36, 40, 44}+56*n. In this case, ata carrier frequency of 6 GHz or more, n=0, 1, 2, 3, 5, 6, 7, or 8.

FIG. 5 relates to a procedure for transmission of control informationand control channel in a 3GPP NR system. Referring to FIG. 5(a), thebase station may add a cyclic redundancy check (CRC) masked with a radionetwork temporary identifier (RNTI) (e.g., an XOR operation) to controlinformation (e.g., Downlink Control Information, DCI) (S502). The basestation may scramble the CRC with an RNTI value determined according tothe purpose/target of each control information. The common RNTI used byone or more terminals may include at least one of a system informationRNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI),and a transmit power control RNTI (TPC-RNTI). In addition, theUE-specific RNTI may include at least one of cell temporary RNTI(C-RNTI) and semi-persistent scheduling (SPS C-RNTI). Thereafter, thebase station may perform rate-matching according to the amount ofresource(s) used for PDCCH transmission (S506) after performing channelcoding (e.g., polar coding) (S504). Subsequently, the base station maymultiplex DCI(s) based on a control channel element (CCE) based PDCCHstructure (S508), apply additional processes (e.g., scrambling,modulation (e.g., QPSK), and interleaving) (S910) for the multiplexedDCI(s), and thereafter, map it to a resource to be transmitted. The CCEis a basic resource unit for the PDCCH, and one CCE may consist of aplurality (e.g., six) resource element groups (REGs). One REG mayconsist of a plurality of (e.g., 12) REs. The number of CCEs used forone PDCCH may be defined as an aggregation level. In 3GPP NR system, 1,2, 4, 8 or 16 can be used. FIG. 5(b) is a diagram illustrating the CCEaggregation level and the PDCCH multiplexing. In this case, the type ofthe CCE aggregation level used for one PDCCH and the CCE(s) transmittedin the control region accordingly are described.

FIG. 6 is a diagram illustrating a control resource set (CORESET) inwhich a physical downlink control channel (PDCCH) in a 3GPP NR systemmay be transmitted.

CORESET is a time-frequency resource in which PDCCH, that is, a controlsignal of a user equipment, is transmitted. Referring to FIG. 6 , theuser equipment may decode the PDCCH mapped in the CORESET by receivingonly time-frequency resources defined by CORESET, instead of attemptingto decode the PDCCH by receiving all the frequency bands. The basestation may configure one or more CORESETs for each cell to the userequipment. CORESET may be configured with up to three consecutivesymbols on the time axis. In addition, CORESET may be configuredcontinuously or discontinuously in 6 PRBs units on the frequency axis.In the embodiment of FIG. 5 , CORESET #1 is configured with consecutivePRBs, and CORESET #2 and CORESET #3 are configured with discontinuousPRBs. CORESET may be located in any symbol in the slot. For example,CORESET #1 in FIG. 5 starts at the first symbol of the slot, CORESET #2starts at the fifth symbol of the slot, and CORESET #9 starts at theninth symbol of the slot.

FIG. 7 is a diagram for setting a PDCCH search space in the 3GPP NRsystem. In order to transmit the PDCCH to the user equipment, eachCORESET may have at least one search space. In the present invention,the search space is all the time-frequency resource combinations(hereinafter, a set of PDCCH candidates) through which the PDCCH of theuser equipment may be transmitted. The search space may include a commonsearch space that the user equipment of the 3GPP NR must commonlyperform a search and a Terminal-specific or UE-specific search spacethat a specific user equipment must perform a search. In the commonsearch space, it is set to monitor the PDCCH that all the userequipments in the cell belonging to the same base station are commonlyset to search. Furthermore, in the UE-specific search space, each userequipment may be set to monitor the PDCCH allocated to each userequipment in different search space positions according to the userequipment. The corresponding UE-specific search space may be partiallyoverlapped with the search space of other user equipments due to thelimited control region to which the PDCCH can be allocated. Monitoringthe PDCCH includes blind decoding PDCCH candidates in the search space.The case where the blind decoding is successful may be expressed thatthe PDCCH is (successfully) detected/received. Furthermore, the casewhere the blind decoding has failed may be expressed that the PDCCH isnot successfully detected/received.

For convenience of explanation, a PDCCH scrambled with a group common(GC) RNTI (or common control RNTI, CC-RNTI) already known to transmit ULscheduling information or DL scheduling information to one or more userequipments is referred to as a (UE) group common (GC) PDCCH or a commonPDCCH. In addition, a PDCCH scrambled with a UE-specific RNTI that aspecific user equipment already knows to transmit UL schedulinginformation or DL scheduling information to one specific user equipmentis referred to as a UE-specific (US) PDCCH.

The PDCCH signals each user equipment or user equipment group of atleast one of information related to resource allocation (i.e., DL grant)of a paging channel (PCH) and a downlink-shared channel (DL-SCH),information related to resource allocation (i.e., UL grant) of UL-SCH,and HARQ information. The base station can transmit a PCH transportblock and a downlink-shared channel (DL-SCH) transmission channelthrough a PDSCH. The base station may transmit data excluding specificcontrol information or specific service data through the PDSCH. Inaddition, the user equipment may receive data excluding specific controlinformation or specific service data through the PDSCH.

The base station may include, in the PDCCH, information on to which userequipment (one or more user equipments) PDSCH data is transmitted andhow the PDSCH data is to be received and decoded by the correspondinguser equipment, and transmit the PDCCH. For example, it is assumed thata specific PDCCH is CRC masked with an RNTI called “A”, and informationon data transmitted using a radio resource (e.g., frequency location)called “B” and a DCI format called “C”, that is, transmission formatinformation (e.g., transport block size, modulation scheme, codinginformation, etc.) is transmitted through a specific subframe. In thiscase, the user equipment in the cell monitors the PDCCH using the RNTIinformation the user equipment has, and when there is more than one userequipment with an “A” RNTI, the corresponding user equipment receivesthe PDCCH and receives the PDSCH indicated by “B” and “C” through theinformation of the received PDCCH.

Table 2 shows the physical uplink control channel (PUCCH) used in thewireless communication system.

TABLE 2 PUCCH format Length in OFDM symbols Number of bits 0 1-2  ≤2 14-14 ≤2 2 1-2  >2 3 4-14 >2 4 4-14 >2

The PUCCH may be used to transmit the following control information.

-   -   Scheduling Request (SR): Information used to request a UL UL-SCH        resource.    -   HARQ-ACK: A response to the PDCCH (which indicates DL SPS        release) and/or a response to a DL data packet on the PDSCH. It        indicates whether PDCCH or PDSCH has been successfully received.        The HARQ-ACK response includes positive ACK (simply ACK),        negative ACK (hereinafter NACK), Discontinuous Transmission        (DTX), or NACK/DTX. Here, the term HARQ-ACK is interchangeably        used with HARQ ACK/NACK and ACK/NACK. In general, ACK may be        represented by 1 and NACK may be represented by 0.    -   Channel State Information (CSI): This is feedback information on        the DL channel. It is generated by the user equipment based on        the CSI-reference signal (RS) transmitted by the base station.        Multiple Input Multiple Output (MIMO)-related feedback        information includes a Rank Indicator (RI) and a Precoding        Matrix Indicator (PMI). CSI may be divided into CSI part 1 and        CSI part 2 according to the information indicated by CSI.

In the 3GPP NR system, five PUCCH formats may be used to support variousservice scenarios and various channel environments and frame structures.

PUCCH format 0 is a format may deliver 1-bit or 2-bit HARQ-ACKinformation. PUCCH format 0 may be transmitted through one OFDM symbolor two OFDM symbols on the time axis and one PRB on the frequency axis.When PUCCH format 0 is transmitted in two OFDM symbols, the samesequence to the two symbols may be transmitted through different PRBs.Through this, the user equipment can obtain a frequency diversity gain.More specifically, the user equipment may determine a value m_(cs) of acyclic shift according to M_(bit) bits UCI (M_(bit)=1 or 2), and map asequence obtained by cyclic-shifting a base sequence having a length of12 to a predetermined value m_(cs) to 12 REs of one PRB of one OFDMsymbol and transmit it. In a case where the number of cyclic shiftsusable by the user equipment is 12 and M_(bit)=1, when the userequipment transmits UCI 0 and UCI 1, the user equipment may arranges thedifference value of the two cyclic shifts to 6. In addition, whenM_(bit)=2 and the user equipment transmits UCI 00, UCI 01, UCI 11, UCI10, the user equipment can arrange the difference of four cyclic shiftvalues to 3.

PUCCH format 1 may deliver 1-bit or 2-bit HARQ-ACK information. PUCCHformat 1 may be transmitted through consecutive OFDM symbols on the timeaxis and one PRB on the frequency axis. Here, the number of OFDM symbolsoccupied by PUCCH format 1 may be one of 4, 5, 6, 7, 8, 9, 10, 11, 12,13, and 14. More specifically, M_(bit)=1 UCI may be BPSK-modulated. Theuser equipment generates a complex valued symbol d(0) by quadraturephase shift keying (QPSK) modulation of M_(bit)=2 UCI and multiplies thegenerated d(0) by a sequence of length 12 to obtain a signal. The userequipment transmits the obtained signal by spreading the even-numberedOFDM symbol to which PUCCH format 1 is allocated through the time axisorthogonal cover code (OCC). PUCCH format 1 determines the maximumnumber of different user equipments multiplexed in the same PRBaccording to the length of the OCC to be used. In the odd-numbered OFDMsymbols of PUCCH format 1, demodulation RS (DMRS) is spread with OCC andmapped.

PUCCH format 2 may deliver Uplink Control Information (UCI) exceeding 2bits. PUCCH format 2 may be transmitted through one OFDM symbol or twoOFDM symbols on the time axis and one PRB on the frequency axis. WhenPUCCH format 2 is transmitted in two OFDM symbols, the same sequence tothe two different OFDM symbols may be transmitted through differentPRBs. Through this, the user equipment can obtain a frequency diversitygain. More specifically, M_(bit) bits UCI (M_(bit)>2) is bit-levelscrambled, QPSK-modulated, and mapped to the PRB(s) of the OFDM symbol.Here, the number of PRBs may be any one of 1, 2, . . . , 16.

PUCCH format 3 or PUCCH format 4 may deliver a UCI exceeding 2 bits.PUCCH format 3 or PUCCH format 4 may be transmitted through consecutiveOFDM symbols on the time axis and one PRB on the frequency axis. Thenumber of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 maybe one of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14. Specifically, theuser equipment modulates M_(bit) bits UCI (M_(bit)>2) with π/2-binaryphase shift keying (BPSK) or QPSK to generate a complex valued symbold(0), . . . , d(Msymb−1). The user equipment may not apply block-wisespreading to PUCCH format 3. However, the user equipment may applyblock-wise spreading to one RB (12 subcarriers) using a length-12PreDFT-OCC so that PUCCH format 4 can have two or four multiplexingcapacities. The user equipment performs transmit precoding (orDFT-precoding) on the spread signal and mapping it to each RE totransmit the spread signal.

In this case, the number of PRBs occupied by PUCCH format 2, PUCCHformat 3, or PUCCH format 4 may be determined according to the lengthand maximum code rate of the UCI transmitted by the user equipment. Whenthe user equipment uses PUCCH format 2, the user equipment can transmitHARQ-ACK information and CSI information together through the PUCCH.When the number of PRBs that the user equipment can transmit is greaterthan the maximum number of PRBs that PUCCH format 2, or PUCCH format 3,or PUCCH format 4 is capable of using, the user equipment may transmitonly the remaining UCI information without transmitting some UCIinformation according to the priority of the UCI information.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configuredthrough the RRC signal to indicate frequency hopping in a slot. Whenfrequency hopping is configured, the index of the PRB to be frequencyhopped may be configured with the RRC signal. When PUCCH format 1, orPUCCH format 3, or PUCCH format 4 is transmitted through N OFDM symbolson the time axis, the first hop may have floor (N/2) OFDM symbols andthe second hop may have ceiling(N/2) OFDM symbols.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured tobe repeatedly transmitted in a plurality of slots. In this case, thenumber K of slots in which the PUCCH is repeatedly transmitted may beconfigured by the RRC signal. The repeatedly transmitted PUCCHs isrequired to start at an OFDM symbol of the same position in each slot,and have the same length. When one OFDM symbol among OFDM symbols of aslot in which the user equipment is required to transmit a PUCCH isindicated as a DL symbol by an RRC signal, the user equipment may nottransmit the PUCCH in a corresponding slot and delay the transmission ofthe PUCCH to the next slot to transmit the PUCCH.

In the 3GPP NR system, a user equipment can performtransmission/reception using a bandwidth less than or equal to thebandwidth of a carrier (or cell). For this, the user equipment may beconfigured with a Bandwidth part (BWP) consisting of a continuousbandwidth which is a part of the bandwidth of the carrier. A userequipment operating according to TDD or operating in an unpairedspectrum may be configured with up to four DL/UL BWP pairs in onecarrier (or cell). In addition, the user equipment may activate oneDL/UL BWP pair. A user equipment operating according to FDD or operatingin paired spectrum can receive up to four DL BWPs on a DL carrier (orcell) and up to four UL BWPs on a UL carrier (or cell). The userequipment may activate one DL BWP and one UL BWP for each carrier (orcell). The user equipment may or may not perform reception ortransmission in a time-frequency resource other than the activated BWP.The activated BWP may be referred to as an active BWP.

The base station may indicate using the downlink control information(DCI) that the user equipment switch from one BWP to another BWP.Switching from one BWP to another BWP by the user equipment may indicatethat the user equipment deactivates the BWP used by the user equipmentand activates the new BWP. In a carrier (or cell) operating in TDD, thebase station may include a Bandwidth part indicator (BPI) indicating theBWP to be activated in the DCI scheduling PDSCH or PUSCH to change theDL/UL BWP pair of the user equipment. The user equipment may receive theDCI scheduling the PDSCH or PUSCH and may identify the DL/UL BWP pairactivated based on the BPI. For a DL carrier (or cell) operating as anFDD, the base station may include a BPI indicating the BWP to beactivated in the DCI scheduling PDSCH to change the DL BWP of the userequipment. For a UL carrier (or cell) operating as an FDD, the basestation may include a BPI indicating the BWP to be activated in the DCIscheduling PUSCH to change the UL BWP of the user equipment.

Hereinafter, a carrier aggregation technique will be described. FIG. 6is a conceptual diagram illustrating carrier aggregation.

Carrier aggregation is a method in which the user equipment uses aplurality of frequency blocks or cells (in the logical sense) includingUL resources (or component carriers) and/or DL resources (or componentcarriers) as one large logical frequency band in order for a wirelesscommunication system to use a wider frequency band. Hereinafter, forconvenience of description, the term “component carrier” is used.

Referring to FIG. 8 , as an example of a 3GPP NR system, a total systembandwidth includes up to 16 a component carriers, and each componentcarrier may be capable of having a bandwidth up to 400 MHz. A componentcarrier may include one or more physically contiguous subcarriers.Although it is shown in FIG. 8 that each of the component carriers hasthe same bandwidth, this is merely an example, and each componentcarrier may have a different bandwidth. Also, although each componentcarrier is shown as being adjacent to each other in the frequency axis,the drawings are shown in a logical concept, and each component carriermay be physically adjacent to one another, or may be spaced apart.

Different center frequencies may be used for each component carrier.Also, one common center carrier may be used in a physically adjacentcomponent carrier. Assuming that all the component carriers arephysically adjacent in the embodiment of FIG. 8 , the center carrier Amay be used in all the component carriers. Further, assuming that therespective component carriers are not physically adjacent to each other,the center carrier A and the center carrier B may be used in each of thecomponent carriers.

When the total system band is extended by carrier aggregation, thefrequency band used for communication with each user equipment may bedefined in units of a component carrier. The user equipment A can use100 MHz, which is the total system band, and performs communicationusing all five component carriers. The user equipments B1 to B5 can useonly 20 MHz bandwidth and perform communication using one componentcarrier. The user equipments C₁ and C₂ can use a 40 MHz bandwidth andperform communication using two component carriers, respectively. Thetwo component carriers may be logically/physically adjacent ornon-adjacent. The user equipment C₁ represents the case of using twonon-adjacent component carriers, and user equipment C₂ represents thecase of using two adjacent component carriers.

FIG. 9 is a diagram for explaining single carrier communication andmulti-carrier communication. Particularly, FIG. 7(a) shows a singlecarrier subframe structure and FIG. 7(b) shows a multi-carrier subframestructure.

Referring to FIG. 9(a), a general wireless communication system performsdata transmission or reception (in a frequency division duplex (FDD)mode) through one DL band and one UL band corresponding thereto. Inanother specific embodiment, a wireless communication system may dividea wireless frame into a UL time unit and a DL time unit in a timedomain, and perform data transmission or reception (in a time divisionduplex (TDD) mode) through the UL/DL time unit. Referring to FIG. 9(b),three 20 MHz CCs may be aggregated into UL and DL, respectively, so thata bandwidth of 60 MHz may be supported. Each CC may be adjacent ornon-adjacent to one another in the frequency domain. FIG. 9(b) shows acase where the bandwidth of the UL CC and the bandwidth of the DL CC arethe same and symmetric, but the bandwidth of each CC may be determinedindependently. In addition, asymmetric carrier aggregation withdifferent number of UL CCs and DL CCs is possible. A DL/UL CC that islimited to a specific user equipment through RRC may be referred to as aconfigured serving UL/DL CC at a specific user equipment.

The base station may be used to communicate with the user equipment byactivating some or all of the serving CCs configured in the userequipment, or by deactivating some CCs. The base station can change theCC to be activated/deactivated, and change the number of CCs to beactivated/deactivated. If the base station allocates a CC available forthe user equipment to a cell-specific or UE-specific, then at least oneof the allocated CCs is deactivated, unless the CC allocation for theuser equipment is completely reconfigured or the user equipment ishandover. One CC that is not deactivated by the user equipment is calleda Primary CC (PCC), and a CC that the base station can freelyactivate/deactivate is called a Secondary CC (SCC). PCC and SCC may bedistinguished based on control information. For example, specificcontrol information may be set to be transmitted and received onlythrough a specific CC, and this specific CC may be referred to as PCCand the remaining CC(s) may be referred to as SCC(s).

Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources.A cell is defined by a combination of DL resources and UL resources,that is, a combination of DL CC and UL CC. A cell may be configured withDL resources alone, or a combination of DL resources and UL resources.If carrier aggregation is supported, the linkage between the carrierfrequency of the DL resource (or DL CC) and the carrier frequency of theUL resource (or UL CC) may be indicated by system information. In thecase of user equipments that are in the RRC_CONNECTED state but notconfigured for carrier aggregation or that do not support carrieraggregation, there is only one serving cell configured with PCell.

As mentioned above, the term “cell” used in carrier aggregation isdistinguished from the term “cell” which refers to a certaingeographical area in which a communication service is provided by onebase station or one antenna group. In order to distinguish between acell referring to a certain geographical area and a cell of carrieraggregation, in the present invention, a cell of a carrier aggregationis referred to as a CC, and a cell of a geographical area is referred toas a cell.

FIG. 10 is a diagram showing an example in which a cross carrierscheduling technique is applied. In particular, in FIG. 10 , the numberof allocated cells (or component carriers) is 3, and cross carrierscheduling technique is performed using CIF as described above. Here, itis assumed that the DL cell #0 is a DL primary component carrier (i.e.,Primary Cell (PCell)), and it is assumed that the remaining componentcarriers #1 and #2 are secondary component carriers (i.e., SecondaryCell (SCell)).

The present invention proposes a method of effectively managing ULresources for a primary component carrier (primary component carrier orprimary cell or PCell) or a secondary component carrier (secondarycomponent carrier or secondary cell or SCell) during a carrieraggregation operation of the user equipment. Hereinafter, the case wherethe user equipment operates by aggregating two component carriers isdescribed, but it is obvious that the present invention can also beapplied to the case of aggregating three or more component carriers.

FIGS. 9 to 10 exemplarily illustrate a subframe structure of a 3GPPLTE-A system, but the present invention may also be applied to a 3GPP NRsystem. In the 3GPP NR system, the subframes in FIGS. 9 to 10 may bereplaced with slots.

Hereinafter, the present invention will be described. In order tofacilitate understanding of the description, each content is describedby separate embodiments, but each embodiment may be used in combinationwith each other.

Embodiment 1: Slot Configuration and Signaling for the Same

FIGS. 11 to 12 illustrate an example of a slot configuration in a mobilecommunication system using TDD.

In the 3GPP NR system, the base station can flexibly change theconfiguration of the slot according to the traffic of users, andconfigure the UE with information on the configuration of the slot(simply, slot-format information (SFI)) through an RRC signal orindicate it through an Layer 1 (L1) (e.g., PDCCH) signal. Herein, theinformation on the configuration of the slot indicates configurationinformation about symbols in a slot. In this case, the symbol means anOFDM symbol, and the OFDM symbol includes a CP-OFDM symbol or aDFT-s-OFDM symbol (or an SC-FDM(A) symbol). Referring to FIGS. 11 to 12, each symbol in the slot may be configured to one of a downlink (DL)symbol, an uplink (UL) symbol, and an Unknown symbol. In this case, theUnknown symbol means a symbol that is neither a DL symbol nor a ULsymbol, and the usage, transmission direction, or symbol type (e.g., DL,UL, and X) thereof can be changed (where X represents Unknown). Forexample, the Unknown symbol is a symbol that is neither a DL symbol noran UL symbol, and may be changed into a DL symbol, an UL symbol, or anUnknown symbol. Some/all of the Unknown symbols in the slot may be usedas a gap for DL-UL switching, or may be used for purposes other than thegap. The Unknown symbol may also be represented as a Flexible symbol,and in this specification, the Flexible symbol and the Unknown symbolare mixed with each other.

Referring to FIG. 11 , a slot may include a plurality of symbols, andeach symbol may be a DL symbol, an Unknown symbol, or an UL symbol. Theslot may include 14 symbols as shown in FIG. 2 , but the number ofsymbols is assumed to be 7 for convenience of description. The Unknownin FIG. 11 may be understood as a symbol for guaranteeing a DL-ULswitching gap. In the case of FIG. 11 , 8 slot formats may be defined.Slot configuration 0 consists of all downlink OFDM symbols. Slotconfiguration 1 consists of 6 downlink symbols and 1 Unknown symbol.Slot configuration 2 consists of 5 downlink symbols, 1 Unknown symbol,and 1 uplink symbol. Slot configuration 3 consists of 4 downlinksymbols, 1 Unknown symbol, and 2 uplink symbols. Slot configuration 4consists of 3 downlink symbols, 1 Unknown symbol, and 3 uplink symbols.Slot configuration 5 consists of 2 downlink symbols, 1 Unknown symbol,and 4 uplink symbols. Slot configuration 6 consists of 1 downlinksymbol, 1 Unknown symbol, and 5 uplink symbols. Slot configuration 7consists of 7 uplink symbols. In the present invention, for convenienceof description, the slot configuration 0 is referred to as a DL-onlyslot and the slot configuration 7 is referred to as a UL-only slot. Theslot structure of FIG. 11 may be extended to a slot consisting of 12 or14 OFDM symbols. In addition, in the slot structure of FIG. 11 , oneslot may include one or more Unknown symbols.

Hereinafter, based on the slot structure of FIG. 12 , a method that abase station indicates configuration information of a slot to a UE willbe described.

As the first method of informing the UE of configuration information ofa slot, the base station may inform the UE of semi-static DL/ULallocation information. In this case, the semi-static DL/UL allocationinformation includes information on the DL/UL configuration in the slot,which is referred to as semi-static slot-format information (semi-staticSFI). The base station may transmit the semi-static DL/UL allocationinformation (or semi-static SFI) cell-specifically (e.g., transmitthrough system information block or cell-specific RRC information) ortransmit it through UE-specific RRC signal. When the UE receives thesemi-static DL/UL allocation information (or semi-static SFI), the UEcan identify the slot configuration of the next slot(s). The semi-staticSFI may include slot configuration information for a set of slotscorresponding to a slot configuration period, and the slot configurationinformation may be repeatedly applied in units of set of slots. Thesemi-static DL/UL allocation information (or semi-static SFI) includesinformation about slot configuration, for example, whether each symbolin the slot is a downlink (hereinafter, DL) symbol, an uplink(hereinafter, UL) symbol, or an Unknown symbol that is neither thedownlink symbol nor the uplink symbol. For reference, the UE may assumethat a symbol for which semi-static DL/UL allocation information (orsemi-static SFI) is not indicated is indicated as ‘Unknown’.

According to an embodiment of the present invention, as a method ofsignaling semi-static DL/UL allocation information (or semi-static SFI),the number of DL symbols, i.e., N_(DL) in each slot may be informed withan assumption by the base station and the UE that a configuration of oneslot always has the order of DL symbol, Unknown symbol and UL symbol.The UE may identify the number of Unknown symbols, i.e., N_(Unknown) inthe slot through other RRC signals. The UE may obtain the number of ULsymbols in the slot as max (0, N_(symbol)−N_(DL)−N_(Unknown)). Here,N_(symbol) is the total number of symbols included in one slot, and max(x, y) is a function that returns a larger value between x and y. Thenumber of Unknown symbols configured through the other RRC signals maybe the same as the number of symbols corresponding to the GAP for DL-ULswitching of the UE. For reference, if the number of bits required toindicate semi-static DL/UL allocation information (or semi-static SFI)of one slot in this manner is K, since a value N_(DL) can have is one of0, 1, . . . , 14 when N_(symbol)=14, it may be satisfied that K=4.

According to an embodiment of the present invention, as another methodof signaling semi-static DL/UL allocation information (or semi-staticSFI), the number of DL symbols, i.e., N_(DL) and the number of Unknownsymbols, i.e., N_(Unknown) in each slot may be informed with anassumption by the base station and the UE that a configuration of oneslot always has the order of DL symbol, Unknown symbol and UL symbol.The UE may obtain the number of UL symbols in the slot as max (0,N_(symbol)−N_(DL)−N_(Unknown)). Here, N_(symbol) is the total number ofsymbols included in one slot, and max (x, y) is a function that returnsa larger value between x and y. Assuming that the base station uses twoN_(Unknown) values, if the number of bits required to indicatesemi-static DL/UL allocation information (or semi-static SFI) of oneslot in this manner is K, since 4 bits are required to indicate N_(DL)which can have a value among 0, 1, . . . , 14 when N_(symbol)=14 and 1bit is required to indicate two N_(Unknown) values, it may be satisfiedthat K=5.

According to an embodiment of the present invention, as yet anothermethod of signaling semi-static DL/UL allocation information (orsemi-static SFI), the number of DL symbols, i.e., N_(DL) and the numberof UL symbols, i.e., N_(UL) in each slot may be informed with anassumption by the base station and the UE that a configuration of oneslot always has the order of DL symbol, Unknown symbol and UL symbol.The UE may obtain the number of Unknown symbols in the slot as max (0,N_(symbol)−N_(DL)−N_(UL)). Here, N_(symbol) is the total number ofsymbols included in one slot, and max (x, y) is a function that returnsa larger value between x and y. If the number of bits required toindicate semi-static DL/UL allocation information (or semi-static SFI)of one slot in this manner is K, assuming that the base station uses avalue one of 0, 1, . . . , 14 as N_(DL) and a value one of 0, 1, . . . ,14 as N_(UL) when N_(symbol)=14, then it may be satisfied that K=8.

As still another method of signaling semi-static DL/UL allocationinformation (or semi-static SFI), X and Y which correspond to the numberof DL symbols and the number of UL symbols may be informed with anassumption by the base station and the UE that a configuration of oneslot always has the order of DL symbol, Unknown symbol and UL symbol. Inaddition, 1 bit may indicate either a UL-centric slot format or aDL-centric slot format. Here, the range of values of X may be greaterthan the range of values of Y. For example, X may have a value ofX_(min)˜N_(symbol), and Y may have a limited value such as 0˜Y_(max). Inthis case, X_(min) is a number greater than or equal to 0 and less thanor equal to N_(symbol). Preferably, X_(min)=7. Here, Y_(max) may begreater than or equal to 0 and less than or equal to X_(min). PreferablyY_(max)=7. If the additional 1 bit indicate a DL-centric slot, thenN_(DL)=X and N_(UL)=Y. If the additional 1 bit indicates a UL-centricslot, then N_(DL)=Y and N_(UL)=X. The UE may obtain the number ofUnknown symbols in the slot as max (0, N_(symbol)−N_(DL)−N_(UL)). Here,N_(symbol) is the total number of symbols included in one slot, and max(x, y) is a function that returns a larger value of x and y. If thenumber of bits required to indicate semi-static DL/UL allocationinformation (or semi-static SFI) of one slot in this manner is K,assuming that X=7, 8, 9, 10, 11, 12, 13, 14 and Y=0, 1, 2, 3, 4, 5, 6, 7when N_(symbol)=14, since 3 bits are required for each case and 1 bit isrequired to indicate to determine whether it is DL-centric orUL-centric, it may be satisfied that K=7.

According to an embodiment of the present invention, as yet stillanother method for signaling semi-static DL/UL allocation information(or semi-static SFI), the starting time and the length of symbolsoccupied by Unknown symbols in a slot may be informed with an assumptionby the base station and the UE that a configuration of one slot alwayshas the order of DL symbol, Unknown symbol and UL symbol. Specifically,it can be assumed that the number of symbols in the slot is N_(symbol),and N_(start) is the position of the OFDM symbol where the Unknownsymbol starts within the slot, and L_(symbols) is the number ofconsecutively assigned Unknown symbols. In addition, it is assumed thatthe position of the OFDM symbol starts from 0. A symbol indication value(SIV) for indicating information to which an Unknown symbol is allocatedin one slot may be determined as follows.

If (L _(symbols)−1)≤floor(N _(symbol)/2)

SIV=N _(symbol)*(L _(symbols)−1)+N _(start)

else

SIV=N _(symbol)*(N _(symbol) −L _(symbols)+1)+(N _(symbol)−1−N _(start))

where L _(symbols)≥1 and shall not exceed N _(symbol) −N_(start).  [Equation 1]

Here, floor (x) is a function that returns the largest integer less thanor equal to x. In addition, the SIV value may have a value between 0 andN_(symbol)*(N_(symbol)+1)/2−1. For example, if a slot has 14 symbols andall of them are Unknown symbols, N_(start)=0 and L_(symbols)=14, soSIV=27. If the Unknown symbols are located at OFDM symbols 4, 5 and 6,SIV=32 since N_(start)=4 and L_(symbols)=3. The SIV values between0˜N_(symbol)*(N_(symbol)+1)/2−1 assumes that there is at least oneunknown symbol within one slot, and it cannot indicate a DL-only slot(i.e., a slot in which all symbols are DL symbols) and a UL-only slot(i.e., a slot in which all symbols are UL symbols).

On the other hand, by adding an additional value to the SIV value, it ispossible to indicate that one slot is composed of all DL symbols or allUL symbols. For example, SIV=N_(symbol)*(N_(symbol)+1)/2 can beindicated to indicate a slot consisting of all DL symbols, andSIV=N_(symbol)*(N_(symbol)+1)/2+1 can be indicated to indicate a slotconsisting of all UL symbols. As another example,SIV=N_(symbol)*(N_(symbol)+1)/2 can be indicated to indicate a slotconsisting of all UL symbols, and SIV=N_(symbol)*(N_(symbol)+1)/2+1 canbe indicated to indicate a slot consisting of all DL symbols. In thisscheme, the SIV ranges from 0 to N_(symbol)*(N_(symbol)+1)/2+1. Thus,the required number of bits is ceil(log₂(N_(symbol)*(N_(symbol)+1)/2+2)) bits. Here, ceil (x) is a functionthat returns the smallest integer greater than or equal to x. Therefore,if N_(symbol)=14, then 7 bits are required.

Meanwhile, some of the SIV values between 0 andN_(symbol)*(N_(symbol)+1)/2−1 may be interpreted to indicate that oneslot is composed of all DL symbols or all UL symbols. For example, anSIV value indicating that the first OFDM symbol of a slot is Unknown andall other symbols are UL may be interpreted as indicating a slotconsisting of all UL symbols. In addition, an SIV value indicating thatthe last OFDM symbol of a slot is Unknown and all other symbols are DLmay be interpreted as indicating a slot consisting of all DL symbols.

When the slot configuration is indicated by using the SIV scheme, aposition of a symbol where Unknown can be located may be limited as amethod for reducing the bits used for the SIV. For example, when thereare total N_(symbol) symbols in one slot, Unknown may be limited to belocated only between OFDM symbol A and OFDM symbol B. Accordingly, theSIV scheme may indicate the start position and the length of the Unknownsymbol within B−A+1 symbols between the OFDM symbol A and the OFDMsymbol B. For example, when A=6 and B=11, the SIV value may be expressedfrom 0 to 20, and 5 bits are required.

When the slot configuration is indicated by using the SIV scheme, thegranularity of a symbol occupied by Unknown may be limited as a methodfor reducing the bits used for the SIV. In the above description, thesymbol occupied by Unknown was in units of one symbol. This can beincreased in units of P symbols. The SIV may indicate the startingposition and the consecutive number of P Unknown symbol groups. Forexample, if P=2, the number of bits required for SIV can be reduced to 5bits.

As another method for signaling semi-static DL/UL allocation information(or semi-static SFI), the slot may be divided into two sub-slots, andthe base station and the UE may assume that a configuration of one slotalways has the order of DL symbol, Unknown symbol and UL symbol. The SIVscheme may be used as a method for indicating the configuration of eachsub-slot. That is, it is possible to indicate the start and endpositions of the Unknown symbols in each sub-slot. Specifically, it canbe assumed that the number of symbols in a sub-slot is N_(sub-symbol),and N_(sub-start) is the position of the OFDM symbol where the Unknownsymbol starts within the sub-slot, and L_(sub-symbols) is the number ofconsecutively assigned OFDM symbols. In addition, it is assumed that theposition of the OFDM symbol starts from 0. A value, SIV, for indicatinginformation to which an Unknown symbol is allocated in one sub-slot maybe determined as follows.

If (L _(sub-symbols)−1)≤floor(N _(sub-symbol)/2)

SIV=N _(sub-symbol)*(L _(sub-symbols)−1)+N _(sub-start)

else

SIV=N _(sub-symbol)*(N _(sub-symbol) −L _(sub-symbols)+1)+(N_(sub-symbol)−1−N _(sub-start))

where L _(sub-symbols)≥1 and shall not exceed N _(sub-symbol) −N_(sub-start).  [Equation 2]

Here, the SIV value may have a value between 0 andN_(sub-symbol)*(N_(sub-symbol)+1)/2−1. The SIV values between 0 andN_(sub-symbol)*(N_(sub-symbol)+1)/2−1 assume that there is at least oneunknown symbol within one sub-slot.

On the other hand, by adding an additional value to the SIV value, it ispossible to indicate that one sub-slot is composed of all DL symbols orall UL symbols. For example, SIV=N_(sub-symbol)*(N_(sub-symbol)+1)/2 canbe indicated to indicate a sub-slot consisting of all DL symbols, andSIV=N_(sub-symbol)*(N_(sub-symbol)+1)/2+1 can be indicated to indicate asub-slot consisting of all UL symbols. As another example,SIV=N_(sub-symbol)*(N_(sub-symbol)+1)/2 can be indicated to indicate asub-slot consisting of all UL symbols, andSIV=N_(sub-symbol)*(N_(sub-symbol)+1)/2+1 can be indicated to indicate asub-slot consisting of all DL symbols. Therefore, the number of bitsrequired to indicate the format of the sub-slot is N_(sub-symbol)*ceil(log₂(N_(sub-symbol)*(N_(sub-symbol)+1)/2+2)) bits. Here, ceil (x) is afunction that returns the smallest integer greater than or equal to x.Thus, if N_(symbol)=14 and N_(sub-symbol)=7, then 5 bits per sub-slotare required and 10 bits are required for one slot.

Meanwhile, some of the SIV values between 0 andN_(sub-symbol)*(N_(sub-symbol)+1)/2−1 may be interpreted to indicatethat one sub-slot is composed of all DL symbols or all UL symbols. Forexample, an SIV value indicating that the first OFDM symbol of asub-slot is Unknown and all other symbols are UL may be interpreted asindicating a sub-slot consisting of all UL symbols. In addition, an SIVvalue indicating that the last OFDM symbol of a sub-slot is Unknown andall other symbols are DL may be interpreted as indicating a sub-slotconsisting of all DL symbols.

When one slot is composed of two sub-slots, slot configurationinformation of one slot may be represented and transmitted asconfiguration information of two sub-slots. That is, if SIV representingconfiguration information of the first sub-slot is referred to as SIV1and SIV representing configuration information of the second sub-slot isreferred to as SIV2, the UE may identify configuration information ofall slots through SIV1 and SIV2. For reference, SIV1 and SIV2 may bejointly encoded and transmitted. As an example of joint encoding, slotconfiguration information may be expressed in the form ofSIV_(joint-encoding)=SVI1*Q+SIV2. In this case, Q may be one greaterthan the largest one of the valid SIV2 values. The UE may obtain SIV2through the remainder of dividing SIV_(joint-encoding) by Q, and obtainSIV1 through (SIV_(joint-encoding)−SIV2)/Q.

In the above description, SIV indicates the start and end symbols of theUnknown symbols. In the same manner, the last DL symbol and the first ULsymbol in a slot may be indicated by the SIV scheme.

As the second method of informing the UE of configuration information ofa slot, SFI which is information on whether the symbols in a slot aredownlink (DL) symbols, uplink (UL) symbols, or an Unknown symbols thatis neither the downlink symbol nor the uplink symbol may be deliveredthrough the GC-PDCCH. In this case, the GC-PDCCH with SFI may bescrambled with a new GC-RNTI to distinguish it from the existingGC-PDCCH. For convenience, this is referred to as SFI-RNTI. Hereinafter,the SFI transmitted through the GC-PDCCH is referred to as Dynamic SFIfrom GC-PDCCH or SFI_GC-PDCCH.

Referring to FIG. 13 , the base station may change the slotconfiguration (or slot format) using the L1 signal, and may transmitinformation on the changed slot configuration (i.e., dynamic SFI) to theUE through the GC-PDCCH. The UE may receive the slot configurationinformation from the GC-PDCCH, and may transmit and receive wirelesssignals according to the slot configuration information. The slotconfiguration information may carry information about the configurationof the current slot in which the SFI_GC-PDCCH is detected. In addition,the slot configuration information may transmit not only theconfiguration of the current slot in which the SFI_GC-PDCCH is detected,but also information on the configuration of the next slot(s) at once.Further, the slot configuration information may transmit information onhow many next slots have the same configuration with the configurationof the current slot, or may deliver configuration information of thecurrent slot and the next slot.

In order to inform the UE of the slot format through the SFI_GC-PDCCH,the base station may inform the UE of slot formats that can be indicatedby the SFI_GC-PDCCH in advance. In this case, the slot formats that canbe indicated by the SFI_GC-PDCCH may be provided to the UE using aUE-specific RRC signal. In other words, the mapping table of slotformats for the UE to receive the SFI_GC-PDCCH to identify the slotformat may be configured in advance by the UE-specific RRC signal. As amethod of informing the UE of the slot formats that can be indicated bythe SFI_GC-PDCCH through the UE-specific RRC signal, whether the symbolis a DL symbol, a UL symbol, or an Unknown symbol may be indicated foreach symbol. Alternatively, the SIV scheme indicating the slotconfiguration information in the semi-static DL/UL allocation (orsemi-static SFI) scheme described above may be used. In another manner,as a method of information the UE of the slot formats that can beindicated by the SFI_GC-PDCCH through the UE-specific RRC signal, DL/ULmay be indicated for symbols indicated as Unknown in the semi-staticDL/UL allocation (or semi-static SFI). For example, if five ‘Unknown’symbols are indicated in the semi-static DL/UL allocation (orsemi-static SFI), the SFI_GC-PDCCH may indicate DL, UL or ‘Unknown’ forthe five ‘Unknown’ symbols. In addition, the slot format of theSFI_GC-PDCCH may be pre-defined between the base station and the UE.

Table 3 exemplifies an SFI_GC-PDCCH that the base station can indicateto the UE. In Table 3, D denotes a DL symbol, U denotes a UL symbol, andX denotes an Unknown symbol. As shown in Table 3, a maximum of two DL/ULswitching may be allowed in one slot.

TABLE 3 Symbol number in a slot index 0 1 2 3 4 5 6 7 8 9 10 11 12 13  0D D D D D D D D D D D D D D  1 U U U U U U U U U U U U U U  2 X X X X XX X X X X X X X X  3 D D D D D D D D D D D D D X  4 D D D D D D D D D DD D X X  5 D D D D D D D D D D D X X X  6 D D D D D D D D D D X X X X  7D D D D D D D D D X X X X X  8 X X X X X X X X X X X X X U  9 X X X X XX X X X X X X U U 10 X U U U U U U U U U U U U U 11 X X U U U U U U U UU U U U 12 X X X U U U U U U U U U U U 13 X X X X U U U U U U U U U U 14X X X X X U U U U U U U U U 15 X X X X X X U U U U U U U U 16 D X X X XX X X X X X X X X 17 D D X X X X X X X X X X X X 18 D D D X X X X X X XX X X X 19 D X X X X X X X X X X X X U 20 D D X X X X X X X X X X X U 21D D D X X X X X X X X X X U 22 D X X X X X X X X X X X U U 23 D D X X XX X X X X X X U U 24 D D D X X X X X X X X X U U 25 D X X X X X X X X XX U U U 26 D D X X X X X X X X X U U U 27 D D D X X X X X X X X U U U 28D D D D D D D D D D D D X U 29 D D D D D D D D D D D X X U 30 D D D D DD D D D D X X X U 31 D D D D D D D D D D D X U U 32 D D D D D D D D D DX X U U 33 D D D D D D D D D X X X U U 34 D X U U U U U U U U U U U U 35D D X U U U U U U U U U U U 36 D D D X U U U U U U U U U U 37 D X X U UU U U U U U U U U 38 D D X X U U U U U U U U U U 39 D D D X X U U U U UU U U U 40 D X X X U U U U U U U U U U 41 D D X X X U U U U U U U U U 42D D D X X X U U U U U U U U 43 D D D D D D D D D X X X X U 44 D D D D DD X X X X X X U U 45 D D D D D D X X U U U U U U 46 D D D D D X U D D DD D X U 47 D D X U U U U D D X U U U U 48 D X U U U U U D X U U U U U 49D D D D X X U D D D D X X U 50 D D X X U U U D D X X U U U 51 D X X U UU U D X X U U U U 52 D X X X X X U D X X X X X U 53 D D X X X X U D D XX X X U 54 X X X X X X X D D D D D D D 55 D D X X X U U U D D D D D D56~ Reserved 255

SFI_GC-PDCCH may include information on a slot configuration of one ormore slots.

When the SFI_GC-PDCCH includes one slot configuration, the SFI_GC-PDCCHmay include/indicate ‘Slot_index_offset’ and ‘Slot_format_index’. If theSFI_GC-PDCCH indicates Slot_index_offset=k and Slot_format_index=i, theUE may interpret the SFI_GC-PDCCH as follows. If the SFI_GC-PDCCH isreceived in slot n, then slot n+k follows slot format i. Here, the slotformat i means the i-th slot format of a plurality of slot formatspreviously designated by the RRC signal. ‘Slot_index_offset’ may not beindicated by the SFI_GC-PDCCH and may be configured in advance in theRRC layer. The UE may use the ‘slot_index_offset’ value configured inadvance by the RRC layer to interpret the SFI_GC-PDCCH.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate ‘Slot_numbers’ and one‘Slot_format_index’. If the SFI_GC-PDCCH indicates Slot_numbers=k andSlot_format_index=i, the UE may interpret the SFI_GC-PDCCH as follows.If the SFI_GC-PDCCH is received in slot n, then k slots from slot nfollow slot format i. Here, the slot format i means the i-th slot formatof a plurality of slot formats previously designated by the i-th slotformat of Table 3 or the RRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate a plurality of‘Slot_format_index’s. If the SFI_GC-PDCCH indicates values correspondingto Slot_format_index [i₁, i₂, . . . , i_(j)], the UE may interpret theSFI_GC-PDCCH as follows. If the SFI_GC-PDCCH is received in slot n, thenslots from slot n to slot n+k−1 follow slot format i₁, slot format i₂, .. . , and slot format i_(j) sequentially. Here, the slot formats i₁, . .. , i_(j) mean i₁-th, . . . , i_(j)-th slot formats of Table 3 or i₁-th,. . . , i_(j)-th slot formats among a plurality of slot formatspreviously designated by the RRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate ‘Slot_numbers’ and a plurality of‘Slot_format_index’s. If the SFI_GC-PDCCH indicates Slot_numbers=k, andvalues corresponding to Slot_format_index [i₁, i₂, . . . , i_(j)], theUE may interpret the SFI_GC-PDCCH as follows. If the SFI_GC-PDCCH isreceived in slot n, then [slot format i₁, slot format i₂, . . . , slotformat i_(j)] is repeated k times from slot n to slot n+j*k−1. Inanother interpretation, when j is a divisor of k, [slot format i₁, slotformat i₂, . . . , slot format i_(j)] is repeated k/j times from slot nto slot n+k−1. Here, the slot formats i₁, . . . , i_(j) mean i₁-th, . .. , i_(j)-th slot formats of Table 3 or i₁-th, . . . , i_(j)-th slotformats among a plurality of slot formats previously designated by theRRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate ‘Slot_numbers’ and a plurality of‘Slot_format_index’. If the SFI_GC-PDCCH indicates Slot_numbers=k andSlot_format_index=[i₁, i₂, . . . , i_(j)], the UE may interpret theSFI_GC-PDCCH as follows. If the SFI_GC-PDCCH is received in slot n, thenslot n through slot n+k−1 follow slot format i₁, slot n+k through slotn+2*k−1 follow slot format i₂, . . . , slot n+(j−1)*k through slotn+j*k−1 follow slot format i_(j). In another interpretation, when j is adivisor of k, slot n through slot n+k/j−1 follow slot format i₁, slotn+k/j through slot n+2*k/j−1 follow slot format i₂, . . . , slotn+(j−1)*k/j through slot n+k−1 follow slot format i_(j). Here, the slotformats i₁, . . . , i_(j) mean i₁-th, . . . , i_(j)-th slot formats ofTable 3 or i₁-th, . . . , i_(j)-th slot formats among a plurality ofslot formats previously designated by the RRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate a plurality of ‘Slot_format_index’and a plurality of ‘Applied_slot_format_index’. If the SFI_GC-PDCCHindicates Slot_format_index=[i₁, i₂, . . . , i_(j)], andApplied_slot_format_index=[a(1), a(2), . . . , a(j)], the UE mayinterpret the SFI_GC-PDCCH as follows. If the SFI_GC-PDCCH is receivedin slot n, then slot n follows slot format i_(a(1)), slot n+1 followsslot format i_(a(2)), . . . , slot n+k−1 follows slot format i_(a(k)).Here, a(1), . . . , a(k) may have a value one of 1, . . . , j. Here, theslot formats i₁, . . . , i_(j) mean i₁-th, . . . , i_(j)-th slot formatsof Table 3 or i₁-th, . . . , i_(j)-th slot formats among a plurality ofslot formats previously designated by the RRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate a plurality of ‘Slot_format_index’and a plurality of ‘Applied_slot_index’. If the SFI_GC-PDCCH indicatesSlot_format_index=[i₁, i₂, . . . , i_(j)] and Applied_slot_index=[b(1),b(2) . . . , b(j)], the UE may interpret the SFI_GC-PDCCH as follows. Ifthe SFI_GC-PDCCH is received in slot n, then slot n+b(1) follows slotformat i₁, slot n+b(2) follows slot format i₂, . . . , slot n+b(j)follows slot format i_(j). Here, b(1), . . . , b(j) are sequentiallyincreased and each has a non-negative integer value. That is, b(1)<b(2)<. . . <b(j). In addition, the slot formats i₁, . . . , i_(j) mean i₁-th,. . . , i_(j)-th slot formats of Table 3 or i₁-th, . . . , i_(j)-th slotformats among a plurality of slot formats previously designated by theRRC signal.

When the UE indicates the plurality of slot configuration information,the SFI_GC-PDCCH may include/indicate a plurality of ‘Slot_format_index’and a plurality of ‘Applied_slot_index’. If the SFI_GC-PDCCH indicatesSlot_format_index=[i₁, i₂, . . . , i_(j)] and Applied_slot_index=[b(1),b(2), . . . , b(j)], the UE may interpret the SFI_GC-PDCCH as follows.If the SFI_GC-PDCC is received in slot n, then slot n+b(1) follows slotformat i₁, slot n+b(1)+b(2) follows slot format i₂, . . . , slotn+b(1)+b(2)+ . . . +b(j) follows slot format i_(j). Here, each of b(1),. . . , b(k) has one of non-negative integer values. In anotherinterpretation, if the SFI_GC-PDCC is received in slot n, then slotn−1+b(1) follows slot format i₁, slot n−1+b(1)+b(2) follows slot formati₂, . . . , slot n−1+b(1)+b(2)+ . . . +b(j) follows slot format i_(j).Here, each of b(1), . . . , b(k) has a natural value. The slot formatsi₁, . . . , i_(j) mean i₁-th, . . . , i_(j)-th slot formats of Table 3or i₁-th, . . . , i_(j)-th slot formats among a plurality of slotformats previously designated by the RRC signal.

In the above method, Slot_numbers may be indicated by the RRC signal andmay not be included in the SFI_GC-PDCCH. In this case, when the UEreceives the SFI_GC-PDCCH, the UE may identify the slot configurationinformation using ‘Slot_numbers’ obtained through the RRC signal.Alternatively, Slot_numbers may be determined according to the period inwhich the SFI_GC-PDCCH is transmitted. For example, if the UE monitorsthe GC-PDCCH through which the Dynamic SFI is transmitted every 4 slots,Slot_numbers may be 4 slots.

The above methods can be described by replacing the slot with a slotincluding at least one unknown symbol configured in the semi-static SFI.In other words, the slot formats indicated by the SFI_GC-PDCCH may besequentially applied to slots including at least one unknown symbolconfigured in the semi-static SFI.

As the third method of informing the UE of configuration information ofthe slot, the configuration of the scheduled slot can be identifiedusing the DCI of the US-PDCCH. For example, if the DCI includes DLsignal or channel (e.g., PDSCH or CSI-RS) scheduling information, the UEmay assume that the symbols for which the DL signal or channel isscheduled in the slot are DL symbols. Although not limited thereto, theDCI may include information on the start position and a length of thePDSCH. In addition, when the DCI includes UL signal or channel (e.g.,PUSCH or SRS) scheduling information, the UE may assume that symbols forwhich the UL signal or channel is scheduled in the slot are UL symbols.Although not limited thereto, the DCI may include information on thestart position and the length of the PUSCH. The (DL/UL grant) DCI may bea DCI scrambled with C-RNTI. Hereinafter, the slot configurationinformation transmitted through the US-PDCCH is referred to as DynamicSFI from US-PDCCH or SFI_US-PDCCH. The SFI_US-PDCCH may provideconfiguration information for the OFDM symbol(s) scheduled in the slot.In the present specification, a signal and a channel may be describedseparately to help the understanding of the present invention, but thesignal generally includes a signal transmitted through a channel, and asignal/channel may be collectively referred to as a signal.

Referring to FIG. 14 , the base station may indicate the start OFDMsymbol index and the end OFDM symbol index of the PDSCH or informationcapable of indicating the above information in the SFI_US-PDCCH carryingdownlink scheduling information. When the UE successfully receives theSFI_US-PDCCH, the UE may identify the start OFDM symbol index and theend OFDM symbol index of the PDSCH or information capable of indicatingthe above information, and may receive the PDSCH by rate-matchingaccording to the scheduling information. Referring to FIG. 14 , a slotin which a PDSCH for a UE is scheduled may be slot n, which is the sameslot as an SFI_US-PDCCH transmission slot. In addition, the slot inwhich the PDSCH for the UE is scheduled may be the n+k-th (where k is aninteger greater than or equal to 1) slot after the SFI_US-PDCCH istransmitted, or slots from the n-th slot in which the SFI_US-PDCCH istransmitted up to the n+L−1-th slot (where L denotes the number of slotsin which PDSCH allocated to the UE is transmitted when assuming slotaggregation). The index of the slot in which the PDSCH for the UE isscheduled may be transmitted in the SFI_US-PDCCH scheduling the PDSCH.Accordingly, the UE may assume that the symbol to which the PDSCH isallocated is a DL symbol.

Referring to FIG. 14 , the base station may indicate the start OFDMsymbol index and the end OFDM symbol index of the PUSCH or informationcapable of indicating the above information in the SFI_US-PDCCH carryinguplink scheduling information. When the UE successfully receives theSFI_US-PDCCH, the UE may identify the start OFDM symbol index and theend OFDM symbol index of the PUSCH or information capable of indicatingthe above information, and may receive the PUSCH by rate-matchingaccording to the scheduling information. Referring to FIG. 14 , a slotin which a PUSCH for a UE is scheduled may be slot n, which is the sameslot as a slot in which SFI_US-PDCCH is transmitted. In addition, theslot in which the PUSCH for the UE is scheduled may be the n+k-th (wherek is an integer greater than or equal to 1) slot after the SFI_US-PDCCHis transmitted, or slots from the n+k-th (where k is an integer greaterthan 0) slot in which the SFI_US-PDCCH is transmitted up to n+k+L−1(where L denotes the number of slots in which PUSCH allocated to the UEis transmitted when assuming slot aggregation). The index of the slot inwhich the PUSCH for the UE is scheduled may be transmitted in theSFI_US-PDCCH scheduling the PUSCH. Therefore, the UE may assume that thesymbol to which the PUSCH is allocated is a UL symbol.

As another example, the base station may transmit a part of the slotconfiguration information through the SFI_GC-PDCCH, and transmit theremaining part through the SFI_US-PDCCH carrying scheduling information.The UE may identify the slot format/configuration when the UE receivesthe SFI_GC-PDCCH and receives the SFI_US-PDCCH. Specifically, theconfigurable slot configuration indication information is divided intotwo steps and transmitted. In the first step (i.e., group common), apartial set of the entire configuration may be indicated, and a specificconfiguration in the set may be indicated in the second step. Referringto FIG. 11 , the base station may bundle eight slot configurations twoby two and transmit four slot configuration information through anSFI_GC-PDCCH, and may transmit one of the two slot configurationsthrough an SFI_US-PDCCH. The UE may identify the entire slotconfiguration by using slot configuration information transmitted bybundle received in the SFI_GC-PDCCH and information indicating one ofthe two slot configurations received in the SFI_US-PDCCH. Through theabove scheme, control overhead of transmitting slot configurationinformation through SFI_GC-PDCCH and SFI_US-PDCCH can be reduced.

The UE transmits an uplink signal earlier than a downlink signal due toa propagation delay. This is called as a timing advance (TA) and a valuefor the TA may be set through an RRC signal. Therefore, when the uplinksymbol is placed immediately after the downlink symbol, the UE needs tosimultaneously receive the downlink symbol and transmit the uplinksymbol. In order to solve this problem, the UE needs a GAP symbol forDL-to-UL switching between the downlink symbol and the uplink symbol.The GAP symbol may be represented as an Unknown symbol. Therefore, if aslot is configured to the UE without an Unknown symbol between a DLsymbol and un UL symbol, an Unknown symbol should be inserted into theslot.

Referring to FIGS. 15 and 16 , when a UE allocated with a DL-only slot(e.g., slot n+k) identifies that the next slot (e.g., slot n+k+1) isconfigured as a UL-only slot, the last G OFDM symbols of the DL-onlyslot may be punctured or not received. Here, G is a gap between the DLand the UL and may be a different value for each UE or cell, and may bea value previously known to the UE and the base station. G may berepresented by the number of OFDM symbols or a predetermined timeinterval.

Referring to FIG. 17 , UL-only may be allocated to the UE as aconfiguration of a future slot (e.g., slot n+k+1) through a GC-PDCCH ora US-PDCCH containing scheduling information at a time point (e.g., slotn) of scheduling. Then, the GC-PDCCH may be transmitted/received in theslot (e.g., slot n+k) immediately before the allocated UL-only slot. Inthis case, the GC-PDCCH of the slot (e.g., slot n+k) immediately beforethe UL-only slot may indicate the slot configuration before the UL-onlyslot, and the UE may use the slot configuration information of theGC-PDCCH received in the slot (e.g., slot n+k) immediately before theUL-only slot in order to identify whether the slot (e.g., slot n+k)immediately before the UL-only slot is a DL-only slot.

Referring to FIG. 18 , UL-only may be allocated to the UE as aconfiguration of a future slot (e.g., slot n+k+1) through a GC-PDCCH ora US-PDCCH containing scheduling information at a time point (e.g., slotn) of scheduling. Then, the GC-PDCCH may be transmitted/received in atleast one (e.g., slot n+k_(i)) among the slots (e.g., slots n+k, n+k+1,. . . ) immediately before the allocated UL-only slot. In this case, theGC-PDCCH may indicate the slot configuration immediately before theUL-only slot (e.g., slot n+k), and the UE may use the slot configurationinformation of the GC-PDCCH received in the most adjacent slot beforethe UL-only slot in order to identify whether the slot (e.g., slot n+k)immediately before the UL-only slot is a DL-only slot.

Referring to FIG. 17 and FIG. 18 , when a UE allocated with a UL-onlyslot identifies that the previous slot is configured as a DL-only slot,the first G OFDM symbols of the UL-only slot may be punctured or notreceived. Here, G is a gap between the DL and the UL and may be adifferent value for each UE or cell, or may be a different value foreach cell, and may be a value previously known to the UE and the basestation. G may be represented by the number of OFDM symbols or apredetermined time interval. For example, when G has a different valuefor each UE, G may be determined using a TA value set between the basestation and the UE. The G value of the UE having a small TA value may begiven by one OFDM symbol, and the G value of the UE having a large TAvalue may be given by two OFDM symbols.

Embodiment 2: Override Slot Configuration Information

As described above, there may be three methods of informing the UE ofslot configuration information, (i) semi-static SFI, (ii) SFI_GC-PDCCH,and (iii) SFI_US-PDCCH. As described above, semi-static SFI is slotconfiguration information configured by an RRC signal, and SFI_GC-PDCCHand SFI_US-PDCCH are slot configuration information indicated by an L1signal. The semi-static SFI may include information indicating thesymbols of the slot as DL symbol, UL symbol, or Unknown symbol. TheSFI_GC-PDCCH may include information indicating symbols of the slot asDL symbol, UL symbol, or Unknown symbol. The SFI_US-PDCCH may includeinformation indicating symbols of the slot as DL symbol or UL symbol.When the UE receives the RRC signal and the L1 signal, the UE shoulddetermine that the symbols of the slot are which one among DL symbol, ULsymbol, and Unknown symbol, and determine whether the signaltransmission is available according to the determined symbols.

In the present invention, the downlink symbol and the uplink symbolconfigured in the semi-static SFI may not be indicated to otherdirections or indicated as Unknown by SFI_GC-PDCCH or SFI_US-PDCCH.However, the Unknown symbol configured in the semi-static SFI may beindicated to another direction by SFI_GC-PDCCH or SFI_US-PDCCH.Accordingly, the problem to be solved in the present invention relatesto a symbol configured as Unknown in the semi-static SFI, unlessotherwise specified.

Override Between SFI_GC-PDCCH

One problem to be solved by the present invention relates to a methodfor a UE to interpret a plurality of SFI_GC-PDCCHs when configurationinformation for one slot is configured to be received in a plurality ofSFI_GC-PDCCHs.

Referring to FIGS. 13 and 19 , the base station may transmit, throughthe SFI_GC-PDCCH, (i) slot configuration information for the currentslot only, (ii) configuration information for the current slot and thenext slot, or (iii) slot configuration information for the current slotand future N slots. The UE may be configured to identify theconfiguration of the current slot or the next N slots after the currentslot upon reception of the SFI_GC-PDCCH according to the slotconfiguration information transmitted through the SFI_GC-PDCCH. Here, Nis an integer greater than or equal to 1. N may be dynamically changed,set through the RRC, or dynamically indicated by the base station to theUE in a set configured by the RRC. Referring to FIG. 19 , whenSFI_GC-PDCCH carries configuration information of a plurality of slots,slot configuration information of one slot may be transmitted by aplurality of SFI_GC-PDCCHs. According to an embodiment of the presentinvention, when the UE receives a plurality of SFI_GC-PDCCHs regardingconfiguration information of one slot from the base station, the basestation and the UE may operate as follows.

-   -   A downlink transmission may be received or an uplink        transmission may be performed by determining the DL symbol, the        UL symbol, or the Unknown symbol by using the information of the        SFI_GC-PDCCH which was most recently received among the        plurality of SFI_GC-PDCCHs. In other words, when one of        SFI_GC-PDCCH among the plurality of SFI_GC-PDCCHs is        successfully received, the DL symbol, the UL symbol, or the        Unknown symbol may be determined using the information of the        corresponding SFI_GC-PDCCH. That is, the UE may assume that the        plurality of SFI_GC-PDCCHs indicate the same configuration of DL        symbol, UL symbol, or Unknown symbol for one slot.    -   A downlink transmission may be received or an uplink        transmission may be performed by determining the DL symbol, the        UL symbol, or the Unknown symbol by using the information of the        SFI_GC-PDCCH configured to be received most recently among a        plurality of SFI_GC-PDCCHs. In other words, when the most recent        SFI_GC-PDCCH among the plurality of SFI_GC-PDCCHs is        successfully received, the DL symbol, the UL symbol, or the        Unknown symbol may be determined using the information of the        corresponding SFI_GC-PDCCH. The UE may assume that the DL        symbol, the UL symbol, or the Unknown symbol indicated by the        previous SFI_GC-PDCCH can be changed in the subsequent        SFI_GC-PDCCH.

For example, when receiving GC-PDCCH for changing slot configurationinformation in two consecutive slots or slots of consecutive periods,there may be a case where one is received and the other is not received.For example, 1) among the two slots, the SFI_GC-PDCCH may not bereceived in the preceding slot while the SFI_GC-PDCCH is receive in thesubsequent slot, or 2) conversely, among the two slots, the SFI_GC-PDCCHmay be received in the preceding slot while the SFI_GC-PDCCH is notreceive in the subsequent slot. In this case, the UE may utilize slotconfiguration information indicated by the successfully receivedSFI_GC-PDCCH for the UE operation. Meanwhile, in the case of 1) and 2),the UE may assume that it has failed to receive the slot configurationinformation from the base station. Accordingly, the UE may performscheduled downlink reception or uplink transmission using the slotconfiguration information currently assumed by the UE withoutchanging/updating the slot configuration information. Alternatively, inthe case of 1) and 2), the downlink reception or uplink transmission ofthe UE may be performed in the following three ways as in the case ofconsecutively receiving the SFI_GC-PDCCH regarding the change of theslot configuration information from the base station on the basis of theslot in which the SFI_GC-PDCCH is received.

-   -   From the next slot of the slot in which the GC-PDCCH is        received, the base station may perform downlink transmission or        uplink reception using the changed slot configuration        information, and the UE may perform downlink reception and        uplink transmission by assuming the changed slot configuration        information.    -   Starting from the slot of the next period of the slot in which        the GC-PDCCH is received in a consecutive transmission interval        which is set periodically, the base station may perform downlink        transmission or uplink reception using the changed slot        configuration information, and the UE may perform downlink        reception and uplink transmission by assuming the changed slot        configuration information.    -   Starting from the slot in which the GC-PDCCH is received, the        base station may perform downlink transmission or uplink        reception using the changed slot configuration information, and        the UE may perform downlink reception and uplink transmission by        assuming the changed slot configuration information.

Override Between SFI_GC-PDCCH and SFI_US-PDCCH

In the proposal of the present invention, the slot configurationinformation may be transmitted in SFI_GC-PDCCH and/or SFI_US-PDCCH.Another problem to be solved by the present invention is related to theoperation of a UE when the UE receives the SFI_GC-PDCCH andSFI_US-PDCCH, but the slot configuration information indicated by theSFI_GC-PDCCH and the slot configuration information indicated by theSFI_US-PDCCH are not identical to each other.

Referring to FIGS. 13 and 14 , the UE may identify the configuration ofthe slot through the slot configuration information (e.g., symbolconfiguration information in the slot) of the SFI_GC-PDCCH (e.g., FIG.13 ), and may identify the configuration of the scheduled slot usingscheduling information (e.g., a DL/UL scheduled OFDM symbol set) of theSFI_US-PDCCH (e.g., FIG. 14 ). The slot configurations obtained throughthe two pieces of information on the same slot may or may not beidentical.

On the other hand, if the slot configuration information transmitted inthe SFI_GC-PDCCH and the slot configuration information transmitted inthe SFI_US-PDCCH do not match with each other (for the scheduledsymbols), the UE may prioritize the SFI_US-PDCCH and discard the slotconfiguration information transmitted in the successfully receivedSFI_GC-PDCCH. That is, the UE may assume that slot configurationinformation in the SFI_GC-PDCCH is not detected (e.g., skips/cancels theoperation after detecting the SFI_GC-PDCCH), and may perform downlinkreception or uplink transmission according to the scheduling informationand the slot configuration information in the SFI_US-PDCCH. That is,regardless of whether the SFI_GC-PDCCH collides with the SFI_US-PDCCH,the UE may always perform PUSCH transmission or PDSCH reception asscheduled through the SFI_US-PDCCH. Meanwhile, the present method may beapplied in symbol units. For example, the UE may assume thatSFI_GC-PDCCH is not detected only for the collision symbol.

Alternatively, if the scheduling information received from theSFI_US-PDCCH is not the same as the slot configuration informationreceived from the SFI_GC-PDCCH (for the scheduled symbols), the UE mayignore the scheduling information by the SFI_US-PDCCH and may notperform uplink transmission (e.g., PUSCH) or downlink transmission(e.g., PDSCH) according to the corresponding scheduling.

For example, if the PDSCH reception interval (e.g., OFDM symbol)indicated by the scheduling information of the SFI_US-PDCCH does notmatch the DL configuration according to the slot configurationinformation of the SFI_GC-PDCCH, the UE may determine that thescheduling information received from the SFI_US-PDCCH is not identicalto the (slot configuration) information received from the SFI_GC-PDCCH.For example, referring to FIGS. 11 and 14 , in case that theSFI_GC-PDCCH indicates the slot configuration 3, only when theSFI_US-PDCCH indicates that the end position of the PDSCH is the fourthOFDM symbol, the slot configuration information of the SFI_GC-PDCCH andthe scheduling information of the SFI_US-PDCCH may be determined tomatch with each other, and the UE may perform PDSCH reception accordingto the scheduling information of the SFI_US-PDCCH.

Similarly, if the PUSCH transmission interval (e.g., OFDM symbol)indicated by the scheduling information of the SFI_US-PDCCH does notmatch the UL configuration according to the slot configurationinformation of the SFI_GC-PDCCH, the UE may determine that thescheduling information received from the SFI_US-PDCCH is not identicalto the (slot configuration) information received from the SFI_GC-PDCCH.For example, referring to FIGS. 11 and 14 , in case that theSFI_GC-PDCCH indicates the slot configuration 3, only when theSFI_US-PDCCH indicates that the end position of the PDSCH is the sixthOFDM symbol, the slot configuration information of the SFI_GC-PDCCH andthe scheduling information of the SFI_US-PDCCH may be determined tomatch with each other, and the UE may perform PUSCH transmissionaccording to the scheduling information of the SFI_US-PDCCH.

As another example, if the start position, the length, or the endposition of the OFDM symbol indicated by the DL scheduling informationof the SFI_US-PDCCH is not included in the DL configuration according tothe slot configuration information of the SFI_GC-PDCCH and overlaps withan Unknown symbol, the UE may determine that the scheduling informationreceived from the SFI_US-PDCCH is not identical to the informationreceived from the SFI_GC-PDCCH. For example, when the SFI_GC-PDCCHindicates that downlink DL transmission is configured with the fourthOFDM symbol and the SFI_US-PDCCH indicates that the PDSCH is present inthe seventh OFDM symbol beyond the corresponding interval, the UE maynot perform the PDSCH reception (e.g., skip/cancel the receivingoperation).

Similarly, if the start position, the length, or the end position of theOFDM symbol indicated by the UL scheduling information of theSFI_US-PDCCH is not included in the UL configuration according to theslot configuration information of the SFI_GC-PDCCH and overlaps with anUnknown symbol, the UE may determine that the scheduling informationreceived from the SFI_US-PDCCH is not identical to the informationreceived from the SFI_GC-PDCCH. For example, when the SFI_GC-PDCCHindicates slot configuration 3 of FIG. 11 and the SFI_US-PDCCH indicatesthe start position of the PUSCH as the fifth OFDM symbol, the UE may nottransmit the PUSCH (e.g., skip/cancel the receiving operation).

For convenience of description, hereinafter, “the case where thescheduling information received from the SFI_US-PDCCH is not identicalto the (slot configuration) information received from the SFI_GC-PDCCH”may be expresses that “(slot configuration) violation” occurs.

Referring to FIG. 20 , when the base station transmits an SFI_US-PDCCHto the UE in the n-th slot and the SFI_US-PDCCH allocates a PDSCH in the(n+k)-th slot (where k is an integer greater than or equal to 1), theUE, which has been allocated the PDSCH from the SFI_US-PDCCH, should beable to determine whether the above-described slot configuration isviolated in order to determine whether the PDSCH is received. As anexample of the present invention, if the SFI_GC-PDCCH is transmitted ina downlink scheduled slot, the UE may determine whether the violationoccurs by using the slot configuration information of the SFI_GC-PDCCHand the scheduling information of the SFI_US-PDCCH. In FIG. 20 , whenthe SFI_US-PDCCH is transmitted in the slot n and the PDSCH transmissionis scheduled in the slot n+k, the UE may determine whether the violationoccurs by using the SFI_GC-PDCCH received in the slot n+k.

Referring to FIG. 21 , when the SFI_GC-PDCCH is not transmitted orreceived in a slot in which a PUSCH (or PDSCH) is scheduled (i.e.,UL-only slot case), the UE may determine whether the scheduled slot isviolated by using slot configuration information of the most recentlyreceived SFI_GC-PDCCH and scheduling information of the SFI_US-PDCCH. Asshown in FIG. 21 , when slot n through slot n+k are scheduled,SFI_GC-PDCCH is received in slot n+k−i, and SFI_GC-PDCCH is not receivedin slot n+k−i+1 to slot n+k, then the UE may determine whether the slotn+k−i+1 to slot n+k are violated using the SFI_GC-PDCCH received in theslot n+k−i.

The UE may be allocated DL-only as a configuration of the future slot(e.g., slot n+k) through SFI_GC-PDCCH or SFI_US-PDCCH includingscheduling information at a scheduled time (e.g., slot n), and theSFI_GC-PDCCH may be transmitted/received in the allocated DL-only slot(e.g., slot n+k). In this case, the SFI_GC-PDCCH of the DL-only slot mayindicate the slot configuration after the DL-only slot, and the UE mayuse slot configuration information of the SFI_GC-PDCCH to identifywhether the next slot (e.g., slot n+k+1) immediately after the DL-onlyis a UL-only slot.

The UE may be allocated DL-only as a configuration of the future slot(e.g., slot n+k) through GC-PDCCH or US-PDCCH including schedulinginformation at a scheduled time (e.g., slot n), and the GC-PDCCH may notbe transmitted/received in the allocated DL-only slot (e.g., slot n+k).In this case, the GC-PDCCH received in the most adjacent slot (e.g.,slot n+k−i) before the DL-only slot may indicate the slot configurationafter the DL-only slot, and the UE may use slot configurationinformation of the GC-PDCCH to identify whether the next slot (e.g.,slot n+k+1) immediately after the DL-only is a UL-only slot.

When a cross-slot scheduling is configured, an operation of a UE thatreceives UL (or DL) scheduling information from a base station is asfollows. When the UE receives scheduling information (i.e., US-PDCCH)for a specific slot, in order to check whether the configuration of thecorresponding slot is changed, the UE monitors GC-PDCCH from thesubsequent slot of a slot in which the US-PDCCH is received from thebase station to the scheduled slot. The monitored slots are referred toas monitoring interval. If the UE does not receive the GC-PDCCH duringthe monitoring interval, the UE may perform PUSCH transmission (or PDSCHreception) in the scheduled slot according to the scheduling informationof the US-PDCCH. If the UE receives one or more GC-PDCCHs during themonitoring interval, the UE may perform or may not perform (e.g.,skip/cancel the corresponding operation) PDSCH reception and PUSCHtransmission according to the slot configuration indicated by the mostrecently received GC-PDCCH (in reference to the scheduled slot) and thescheduling information.

FIGS. 19, 22 and 23 illustrate an operation of a UE receiving schedulinginformation. The UE may be scheduled for PDSCH reception or PUSCHtransmission in slot n+3 through US-PDCCH in slot n. In this case, theUS-PDCCH may indicate that the slot configuration of the slot n+3 is A.The UE may set slots from a slot after receiving the US-PDCCH to thescheduled slot, that is, slot n+1, slot n+2, and slot n+3 as themonitoring interval. The UE may monitor the GC-PDCCH during themonitoring interval. In this case, GC-PDCCH for transmitting slotconfiguration information of slot n+3 may be received in slot n+1, slotn+2, and slot n+3, respectively. In this case, the GC-PDCCH of slot n+1,slot n+2, and slot n+3 may indicate the slot configuration of slot n+3as slot format B, slot format C, and slot format D, respectively. Inthis case, the UE may determine the information most adjacent to slotn+3, that is, the slot configuration of slot n+3 as the slot format D.Accordingly, the UE may or may not perform PDSCH reception or PUSCHtransmission (e.g., skip/cancel the corresponding operation) in slot n+3based on (i) slot configuration according to slot format D and (ii)scheduling information received in slot n. If the GC-PDCCH is notreceived during the monitoring interval, the UE may perform PDSCHreception or PUSCH transmission in slot n+3 according to the informationscheduled in slot n.

As an example of performing or not performing PDSCH reception or PUSCHtransmission according to the scheduling information, when the PDSCH(PUSCH) is scheduled, the UE may perform PDSCH reception (or PUSCHtransmission) if the OFDM symbol in which PDSCH (or PUSCH) is allocatedis still configured as DL (or UL) in the most recently received GC-PDCCHwithin the monitoring interval. As another example of performing or notperforming PDSCH reception or PUSCH transmission according to thescheduling information, the UE may perform PDSCH reception (or PUSCHtransmission) if the slot configuration identified when the PDSCH (orPUSCH) is scheduled and the slot configuration identified throughGC-PDCCH most recently received within a monitoring interval areidentical with each other, and otherwise, may not perform the PDSCHreception (or PUSCH transmission). If the slot configuration informationof the GC-PDCCH and the US-PDCCH is different, UL transmission may beprohibited since it can generate an interference signal, and only DLreception may be allowed. Herein, the PDSCH/PUSCH scheduled through theUS-PDCCH has been described as an example. However, the presentinvention can be applied to uplink/downlink control signals such as(non-)periodically transmitted and received reference signals, UCI, SRS,and the like. In this case, the same operation may be configured inunits of an OFDM symbol or an RB in which a corresponding control signalis transmitted. In this case, the transmission of the nonperiodic signalmay be scheduled through the US-PDCCH.

In another embodiment, slot configuration information may be transmittedalong with downlink or uplink scheduling information through theUS-PDCCH. In this case, the slot determination method of the UE is asfollows.

FIG. 24 exemplarily illustrates an operation in which slot configurationinformation is included in the US-PDCCH. When the slot format of FIG. 11is informed, the bit size of the slot configuration information in theUS-PDCCH may be 3 bits. On the other hand, the format/configuration ofthe slot is not limited to only DL and UL, and there may beconfigurations such as DL, UL, any, sidelink, blank, and the like. Inthis case, the bit size of the slot configuration information may bedetermined depending on the number of slot configuration information.Referring to FIG. 24 , if the reception/detection of the GC-PDCCH (slotconfiguration information) is successful through the CRC check (S2402,S2404, yes), the UE(s) may perform uplink transmission and downlinkreception in the corresponding slot according to the slot configurationinformation of the GC-PDCCH without using slot configuration information(e.g., 3-bit information) in the US-PDCCH. (S2406). Meanwhile, if thereception/detection of the GC-PDCCH is failed through the CRC check(S2402, S2404, no), but the CRC check of the US-PDCCH is successful(S2408), then the UE may identify the uplink/downlink/Unknownconfiguration of the symbols in the slot by using slot configurationinformation (e.g., 3) in the US-PDCCH (S2410, yes), and may performuplink transmission and downlink reception in the corresponding slot(S2412). If the slot configuration information cannot be read from theUS-PDCCH, the UE may not perform uplink transmission and downlinkreception in the corresponding slot (S2414). On the other hand, unlikethe example of the figure, the UE may identify the slot configuration byreceiving only the US-PDCCH, without receiving the GC-PDCCH (slotconfiguration information). That is, if the US-PDCCH (slot configurationinformation) is successfully received/detected, the UE may not receivethe GC-PDCCH (slot configuration information). In this case, notreceiving the GC-PDCCH (slot configuration information) means thatskipping the decoding of the GC-PDCCH or skipping/canceling an operationaccording to the slot configuration information even though the GC-PDCCHis successfully detected (for a symbol set scheduled by US-PDCCH (slotconfiguration information)). In addition, when the GC-PDCCH (slotconfiguration information) has configuration information regarding aplurality of slots, not receiving the GC-PDCCH may be applied only toslots scheduled by the US-PDCCH.

Meanwhile, slot configuration information in the US-PDCCH through whichuplink or downlink scheduling information is transmitted may bedetermined according to the number of slot configurations that the basestation can transmit. In more detail, the slot configuration informationtransmitted on the US-PDCCH may be the same as the slot configurationinformation transmitted on the GC-PDCCH. Referring to FIG. 11 , slotconfiguration information in the GC-PDCCH may indicate one of eight slotconfigurations, and slot configuration information in the US-PDCCH maycarry the same information. On the other hand, through the slotconfiguration information in the US-PDCCH, the number of cases less thanthe number of cases that can be transmitted in the GC-PDCCH may betransmitted. For example, referring to FIG. 11 , the slot configurationinformation in the GC-PDCCH may indicate one of eight slotconfigurations, and the slot configuration information in the US-PDCCHmay one of four slot configurations (e.g., specific four slotconfigurations among eight slot configurations 0 to 7) through two bits.

As another example, the slot configuration information in the US-PDCCHin which downlink scheduling information is transmitted may indicate aposition where a downlink OFDM symbol ends in a slot. For example, whenthe base station uses the slot configuration 5, it can be informed thatthe downlink is transmitted up to the second OFDM symbol. A downlinkscheduled UE may identify the ending time of the downlink OFDM symbolfrom the slot configuration information (e.g., 3 bits), and maysuccessfully receive the downlink using the above information. Inaddition, an uplink scheduled UE may identify the ending time of thedownlink OFDM symbol from the slot configuration information, and mayidentify the starting time of the uplink OFDM symbol according to the GPconfiguration.

In addition, the slot configuration information in the US-PDCCH in whichuplink scheduling information is transmitted may indicate a positionwhere an uplink OFDM symbol starts in a slot. For example, when usingthe slot configuration 5, it can be informed that the uplinktransmission starts from the fourth OFDM symbol. An uplink scheduled UEmay identify the starting time of the uplink OFDM symbol from the slotconfiguration information, and may use the information for uplinktransmission. Similarly, a downlink scheduled UE may identify thestarting time of the uplink OFDM symbol from the slot configurationinformation, and may identify the ending time of the downlink OFDMsymbol according to the GP configuration.

When the base station and the UE identifies the semi-static SFI, theabove-described slot configuration information may indicate, through 1bit, whether the slot configuration used by the base station isidentical to the semi-static SFI. If the slot configuration informationis 0, it may indicate that the slot configuration used by the basestation is identical to the semi-static SFI, and if the slotconfiguration information is 1, it may indicate that the slotconfiguration used by the base station is different from the semi-staticSFI. The UE may determine whether to perform an operation according tothe information scheduled by the US-PDCCH according to the slotconfiguration information. If the slot configuration information is 0,since the slot configuration used by the base station is identical tothe semi-static SFI, the UE may perform scheduled uplink transmission ordownlink reception based on the semi-static SFI. If the slotconfiguration information is 1, since the slot configuration used by thebase station is different from the semi-static SFI, the UE may notperform scheduled uplink transmission or downlink reception.

When the base station and the UE identifies the semi-static SFI, theabove-described slot configuration information may be determinedaccording to the semi-static SFI. For example, when the semi-static SFIrepresents the slot configuration information i, and the slotconfiguration information for informing the four different slotconfigurations in the US-PDCCH is 2-bit information, 00 may representslot configuration information i, 01 may represent slot configurationinformation i+j₁, 10 may represent slot configuration information i+j₂,and 11 may represent slot configuration i+j₃. Here, j₁, j₂, and j₃ areused to indicate different slot configuration information, and may bepredetermined according to the semi-static SFI and configurationinformation. That is, four different slot format information isindicated, one of which can be set to be identical to the semi-staticSFI (bit 00). The UE may perform uplink transmission or downlinkreception scheduled on the US-PDCCH using semi-static SFI. As anotherexample, instead of informing slot configuration information, a methodof designating an increase and a decrease with respect to the number ofsymbols of DL or UL may be considered. That is, the present operation isan operation of changing the slot configuration in comparison with theslot configuration indicated by the semi-static SFI, and may specify,for example, an increase of DL. As an example, when the semi-static SFIis DL(a)/Unknown(1)/UP(6−a), the base station may have four options of 1increase/2 increase/1 decrease/as is for a. The base station mayflexibly change the number of DL/ULs, rather than changing thepredefined slot format and configuration information, by transmittingthe selected option to the UE through 2-bit information.

When the base station and the UE identifies the semi-static SFI, theslot configuration information may be determined according to theoperation of the UE indicated by the US-PDCCH and the semi-static SFI.For example, the US-PDCCH may indicate the UE whether downlink receptionor uplink transmission according to scheduling information can beperformed assuming semi-static SFI. In more detail, when 1-bit slotconfiguration information in the US-PDCCH is set to 0, assuming thesemi-static SFI, a downlink reception operation or an uplinktransmission operation may be performed according to schedulinginformation of the US-PDCCH. On the other hand, if the 1-bit slotconfiguration information in the US-PDCCH is set to 1, the UE mayperform nothing for downlink reception and uplink transmissionregardless of the scheduling information of the US-PDCCH.

Referring to FIG. 11 , when the slot configuration configured in thesemi-static SFI is 4 and the base station uses the slot configuration 5,the uplink scheduled UE may perform uplink transmission using the 5th,6th, and 7th OFDM symbols. In this case, although the base station hasallocated the fourth OFDM symbol to the uplink, the UE may use it as aDL-UL switching gap. Accordingly, in this case, the base station may setthe 1-bit slot configuration information in the US-PDCCH to 0, so thatthe UE performs uplink transmission in the corresponding slot, and thebase station receives the corresponding uplink from the UE. However,when the slot configuration configured in the semi-static SFI is 4 andthe base station uses the slot configuration 3, the uplink scheduled UEmay not be able to transmit with the slot configuration configured inthe semi-static SFI. Therefore, in this case, the base station may setthe 1-bit slot configuration information in the US-PDCCH to 1, so thatthe UE does not transmit via uplink in the corresponding slot. Referringto FIG. 11 , when the slot configuration configured in the semi-staticSFI is 4 and the base station uses the slot configuration 3, thedownlink scheduled UE may perform downlink reception using the secondand third OFDM symbols. In this case, the base station has allocated thefourth OFDM symbol to the downlink, but the UE may ignore it and performreception. Accordingly, in this case, the base station may set the 1-bitslot configuration information in the US-PDCCH to 0, so that the UEperforms downlink reception in the corresponding slot, so that the UEcan perform downlink reception from the base station. However, when theslot configuration configured in the semi-static SFI is 4 and the basestation uses the slot configuration 5, the downlink scheduled UE cannotperform downlink reception. In this case, the base station may set the1-bit slot configuration information in the US-PDCCH to 1, so that theUE does not perform the reception via downlink in the correspondingslot.

When the base station and the UE identify the semi-static SFI, the slotconfiguration information in the US-PDCCH may be determined according towhether the US-PDCCH is related to uplink transmission or downlinktransmission, and semi-static SFI. For example, the downlink scheduledUE may be informed of only the slot configuration for monitoring aninterval (e.g., UL) for which downlink transmission should not bemonitored when it follows the semi-static SFI, and the uplink scheduledUE may be informed of only the slot configuration for transmitting in aninterval (e.g., DL) for which uplink transmission should not beperformed when it follows the semi-static SFI. For example, referring toFIG. 11 , if slot configuration 4 is used as the slot configurationconfigured in the semi-static SFI, only slot configuration informationfor slot configurations 5, 6 and 7 may be transmitted to the uplinkscheduled UE, and only slot configuration information for slotconfigurations 0, 1 and 2 may be transmitted to the downlink scheduledUE. According to the present scheme, the size of the required slotconfiguration information may vary according to the slot configurationconfigured in the semi-static SFI. In addition, the size of the requiredslot configuration information may vary according to uplink anddownlink.

In order to inform the UE of the slot configuration, the US-PDCCH may betransmitted by scrambling with different RNTIs. One or more RNTIs may beallocated to inform one UE of a slot configuration, or several RNTIs maybe generated using one allocated RNTI. For example, several RNTIs may begenerated from one RNTI using inter-leavers having a predeterminedpattern. In addition, several RNTIs may be generated from one RNTI usingscrambles of a predetermined pattern. Patterns for generating an RNTI inthe UE may be predetermined between the base station and the UE. Theslot format and the configuration of the slot may be identified bydetecting the US-PDCCH scrambled with a certain RNTI among differentRNTIs.

The RNTI used in the present scheme may be determined according to theslot configuration. In this case, RNTI means a UE-specific RNTI definedto indicate the slot configuration information. Referring to FIGS. 5 and11 , the base station may scramble the US-PDCCH by selecting one ofeight RNTIs according to the current slot configuration. For example,the RNTI used for the US-PDCCH scheduling the downlink may be determinedaccording to the position where the downlink OFDM symbol ends. Inaddition, the RNTI used for the PDCCH scheduling the uplink may bedetermined according to the position where the uplink OFDM symbolstarts. In addition, in this scheme, the RNTI may be determinedaccording to the slot configuration configured in the semi-static SFI.When the base station and the UE identify the slot configurationconfigured in the semi-static SFI, referring to FIGS. 5 and 11 , theRNTI may be determined according to the relative difference between thecurrent slot configuration of the base station and the slotconfiguration configured in the semi-static SFI. For example, when theslot configuration configured in semi-static SFI is slot configuration iand four RNTIs are valid, the first RNTI may indicate slot configurationi which is configured in the semi-static SFI, the second RNTI mayindicate slot configuration. i+j₁, the third RNTI may indicate the slotconfiguration i+j₂, and the fourth RNTI may indicate the slotconfiguration i+j₃. Here, j₁, j₂, and j₃ may be predetermined toindicate different slot configurations. That is, four different slotformat information is indicated and one of them may be set to beidentical to the semi-static SFI (e.g., bit 00). When the BS and the UEidentify the slot configuration configured in the semi-static SFI, inthis scheme, the RNTI may be determined according to the operation ofthe UE informed by the US-PDCCH and the slot configuration configured inthe semi-static SFI. For example, when two RNTIs are valid, when thefirst RNTI is used, the operation scheduled in the US-PDSCH may beperformed by assuming the slot configuration configured in thesemi-static SFI, and when the second RNTI is used, the operationscheduled in the US-PDSCH may not be performed. As another example,instead of informing slot configuration information, an increase and adecrease with respect to the number of symbols of DL or UL may bedesignated. That is, the operation is for changing the slot format incomparison with the semi-static SFI and may specify, for example, anincrease of DL. As an example, when the semi-static SFI isDL(a)/Unknown(1)/UP(6−a), the base station may have four options of 1increase/2 increase/1 decrease/as is for a. The base station mayflexibly change the number of DL/ULs, rather than changing thepredefined slot format and configuration information, by transmittingone of the four option to the UE through 2-bit information.

FIG. 25 is a block diagram of a receiver when a slot configuration isinformed using RNTI. The receiver may include a step of estimate andcompensate the channel using the DM-RS pattern (S2502); a step of (QPSK)demodulation (S2504); a step of channel decoding (S2506); a step ofchecking the CRC with all possible RNTIs (S2508); and a step ofdetermining the success of PDCCH decoding according to the CRC check(S2510). The receiver checks the CRC using all valid RNTIs to indicatethe slot configuration. At this time, if only one CRC is valid and allother CRCs are invalid, slot configuration information and correspondingoperation may be identified from the RNTI which provided the valid CRC.In this case, RNTI means a UE-specific RNTI defined to indicate the slotconfiguration information.

FIG. 26 illustrates a situation that may occur when the slotconfiguration used by the base station and the slot configuration usedby the UE are different. In FIG. 26 , an actual slot format is a slotconfiguration actually used by the base station, and a UE decision is aslot configuration recognized by the UE. As described above, the basestation may transmit a GC-PDCCH (dynamic SFI) to inform the UE(s) of theslot configuration. However, a specific UE may fail to receive theGC-PDCCH (dynamic SFI) transmitted from the base station. In this case,the UE may not identify whether the base station has transmitted theGC-PDCCH to indicate the slot configuration, the UE may operate in theslot configuration that the base station is expected to use.

Referring to FIG. 26(a), when the base station uses slot configuration 2and the UE uses slot configuration 0 (see FIG. 11 ), the downlinkscheduled UE receives a signal by determining that all the slots aredownlink OFDM symbols. Therefore, since the UE receives a signal even intwo OFDM symbols not allocated to the downlink, the probability offailing to decode the downlink signal is increased, and the UE energy iswasted. In addition, when the log likelihood ratio (LLR) valuescorresponding to two OFDM symbols not allocated to the downlink arestored in the soft buffer, performance degradation may occur whenretransmission is performed. In addition to the above problems, resourceconsumption for downlink retransmission may occur. Referring to FIG.26(b), when the base station uses slot configuration 4 and the UE usesslot configuration 5 (see FIG. 11 ), the uplink scheduled UE startsuplink transmission from the fourth OFDM symbol. However, since theuplink transmission is performed from the fifth OFDM symbol according tothe slot configuration of the base station, the base station cannotreceive an uplink signal due to the incorrect uplink transmission of theUE. In addition, since an erroneous uplink signal is transmitted to theGP for preventing downlink-uplink interference, interference may occurin the neighboring UE receiving the downlink, thereby degrading downlinkreception performance of the neighboring UE.

As an example for solving the above-described problems, if the UE doesnot successfully receive the slot configuration information transmittedon the GC-PDCCH (i.e., the GC-PDCCH is not detected), the UE may notperform transmission on the scheduled uplink symbol, may not receivescheduled downlink symbol, or may not perform both uplink transmissionand downlink reception. When the user does not receive the downlinkscheduled downlink symbol, the base station may transmit informationagain through HARQ retransmission. When the user does not transmit theuplink scheduled uplink symbol, the base station may transmit uplinkscheduling information again to allow the UE to perform uplinktransmission. However, the above-described scheme does not use resourcesallocated in the scheduled slots, resulting in waste of resources, andadditional delay time occurs because a retransmission or reschedulingscheme is required.

As another example, the base station and the UE may define a semi-staticSFI to be used in advance. If the UE successfully receives the slotconfiguration information transmitted through the GC-PDCCH (i.e., theGC-PDCCH is detected), the UE may operate according to the indicatedslot format. On the other hand, if the UE does not successfully receivethe slot configuration information transmitted through the GC-PDCCH(i.e., the GC-PDCCH is not detected), the UE may perform uplinktransmission or downlink reception according to the semi-static SFI.

Override between SFI and periodic signal #1 One of the problems to besolved by the present invention relates to a method of determiningwhether to transmit/receive a periodic signal configured by RRC to a UE,that is, an operation of a UE for determining a direction of a symbolusing information on slot configuration of SFI_GC-PDCCH. The problemaddressed here includes a case where the reception of the SFI_GC-PDCCHfails. In addition, the problem addressed here is when the UE does notreceive the SFI_US-PDCCH.

The periodic signal collectively refers to all DL/UL signals configuredto be periodically transmitted by the higher layer (e.g., RRC). In the3GPP NR system, a periodically transmitted UL signal configured in theRRC layer includes a periodic sounding reference signal (SRS), ascheduling request (SR), a periodic CSI, a semi-persistent PUSCH(SPS-PUSCH), and the like. Further, in the 3GPP NR system, aperiodically transmitted DL signal includes a channel state informationreference signal (CSI-RS), an SPS-PDSCH, and the like. The SR and theperiodic CSI are transmitted through PUCCH. Specifically, the basestation may inform the UE of the slot-period/offset and the transmissionresource (e.g., OFDM symbol(s) in the slot) of the periodic signalthrough the RRC signal.

Unlike when receiving scheduling information through the SFI_US-PDCCH,for a UE configured to transmit or receive a periodic signal, there isno SFI_US-PDCCH to obtain slot configuration information with regard toa slot in which transmission/reception of the scheduled signal when theinformation scheduled for the UE is not present. Therefore, whenscheduling information is not received through the SFI_US-PDCCH, a UEoperation for performing periodic UL transmission or periodic DLreception needs to be defined. In addition, a method for determining theslog configuration to determine whether to perform, by the UE configuredto perform transmission/reception periodically without schedulinginformation, transmission of a periodic signal or reception of aperiodic signal in a slot (hereinafter, referred to as a periodic slot)configured to transmit/receive periodically.

An operation of a UE that periodically performs transmission/receptionwithout receiving scheduling information through SFI_US-PDCCH is asfollows. First, the UE may define slots from a slot fortransmitting/receiving a periodic signal of the current period to a slotfor transmitting/receiving a periodic signal of the next period as amonitoring interval. The UE may identify the monitoring interval throughthe RRC signal or may determine it according to the period in which theSFI_GC-PDCCH is transmitted. Next, the UE may monitor the SFI_GC-PDCCHincluding the slot configuration information for thetransmission/reception slot of the next period during the monitoringinterval. For example, when the UE is configured to periodicallytransmit an uplink signal (e.g., periodic SRS, SR, periodic CSI,SPS-PUSCH) in a specific time-frequency resource (e.g., OFDM symbol(s))(in each slot which is periodically configured), the UE may transmit theperiodic signal in the time-frequency resource (in the correspondingslot) if the time-frequency resource of the periodic signal (in the slotwhich is periodically configured) is indicated as an uplinkconfiguration through the SFI_GC-PDCCH. On the other hand, when the UEis configured to periodically transmit an uplink signal (e.g., periodicSRS, SR, periodic CSI, SPS-PUSCH) in a specific time-frequency resource(e.g., OFDM symbol(s)) (in each slot which is periodically configured),the UE may not transmit the periodic signal in the time-frequencyresource (in the corresponding slot) (e.g., skip/cancel the transmissionoperation) if the time-frequency resource of the periodic signal (in theslot which is periodically configured) is indicated as not an uplinkconfiguration (e.g., downlink (DL) symbol or Unknown symbol) through theSFI_GC-PDCCH. Similarly, when the UE is configured to periodicallytransmit a downlink signal (e.g., CSI-RS, SPS-PDSCH) in a specifictime-frequency resource (e.g., OFDM symbol(s)) (in each slot which isperiodically configured), the UE may receive the periodic signal in thetime-frequency resource (in the corresponding slot) if thetime-frequency resource of the periodic signal (in the slot which isperiodically configured) is indicated as a downlink configurationthrough the SFI_GC-PDCCH. On the other hand, when the UE is configuredto periodically receive a downlink signal (e.g., CSI-RS, SPS-PDSCH) in aspecific time-frequency resource (e.g., OFDM symbol(s)) (in each slotwhich is periodically configured), the UE may not receive the periodicsignal in the time-frequency resource (in the corresponding slot) (e.g.,skip/cancel the transmission operation) if the time-frequency resourceof the periodic signal (in the slot which is periodically configured) isindicated as not a downlink configuration (e.g., uplink (UL) symbol orUnknown symbol) through the SFI_GC-PDCCH. In addition, when the UE doesnot receive the SFI_GC-PDCCH for the time-frequency resource (e.g., OFDMsymbol(s)) of the periodic signal (in a periodically configured slot)(i.e., if the SFI_GC-PDCCH is not detected) the UE may not transmit theperiodic signal (e.g., skip/cancel transmission operation). In thiscase, the specific time-frequency resource includes uplink and downlinktransmission/reception resources in an OFDM symbol and/or RB unit. Forexample, the specific time-frequency resource may be defined as aspecific OFDM symbol or OFDM symbol set in a slot.

As another example, the UE may perform transmission/reception of asignal (i.e., a periodic signal) originally configured to periodicallyperform regardless of reception/confirm of the GC-PDCCH during themonitoring interval. In this case, the UE may transmit/receive some/allof the periodic signals, for example, signals having high importancesuch as RS, ACK/NACK, SRS, and the like, without checking slotconfiguration information (e.g., SFI_GC-PDCCH). In this case, the UE mayperform the transmission/reception operation on the assumption that thebase station properly performs scheduling for transmission and receptionof the corresponding periodic signal, so that no collision occurs.

Furthermore, the ACK/NACK (of the periodic signal) may be transmitted bythe UE without always checking the slot configuration information of theGC-PDCCH. The PUCCH for transmitting ACK/NACK may be allocated to one ormore last OFDM symbols in a slot, and the UE assumes that symbolscorresponding to the PUCCH are allocated at least UL (regardless of theGC-PDCCH slot configuration information). Can always transmit PUCCH. Inthis case, the periodic ACK/NACK refers to ACK/NACK indicating whetherthe reception of the SPS-PDSCH configured to receive periodically.

FIG. 22 illustrates an operation of a UE when periodically transmittingand receiving in a state where scheduling information is not receivedfor a certain period. Referring to FIG. 22 , the UE may be configured totransmit and receive a periodic signal in slot n and slot n+3. In orderto determine the possibility of periodic signal transmission andreception in slot n+3, a monitoring interval may be defined as slot n+1,slot n+2, and slot n+3. In this case, SFI_GC-PDCCH of slot n+1, slotn+2, and slot n+3 may indicate the slot configuration of slot n+3 asslot format B, slot format C, and slot format D, respectively. In thiscase, the UE determines that the slot configuration indicated by theSFI_GC-PDCCH transmitted in the slot closest to the periodic slot n+3(that is, slot n+2) (that is, slot configuration D) is the slotconfiguration of slot n+3. Based on the slot configuration D, theperiodic signal transmission/reception may be performed/not performed inthe slot n+3.

Override Between SFI and Periodic Signal #2

One of the problems to be solved by the present invention relates to amethod of determining whether to transmit/receive a periodic signalconfigured by RRC to a UE, that is, an operation of a UE for determininga direction of a symbol using information on slot configuration ofSFI_US-PDCCH. In this case, a method of determining a configuration ofthe corresponding slot by a UE when a transmission of a downlink datachannel or a downlink shared channel (e.g., PDSCH) or a transmission ofan uplink data channel or an uplink shared channel (e.g., PUSCH) isscheduled in a slot (hereinafter, referred to as a periodic slot) in aslot for performing transmission or reception of a periodic signal(hereinafter, referred to as a periodic slot) is scheduled to a UEconfigured to perform transmission/reception of a periodicsignal/channel from a base station will be described. The problemaddressed here is that the UE is configured not to monitor GC-PDCCH(dynamic SFI) or is configured to monitor GC-PDCCH (dynamic SFI) butfails to receive it (e.g., failure to detect GC-PDCCH (dynamic SFI)).

The periodic signal collectively refers to all DL/UL signals configuredto be periodically transmitted by the higher layer (e.g., RRC). In the3GPP NR system, a periodically transmitted UL signal configured in theRRC layer includes a periodic SRS, an SR, a periodic CSI, an SPS-PUSCH,and the like. Further, in the 3GPP NR system, a periodically transmittedDL signal includes a CSI-RS, an SPS-PDSCH, and the like. The SR and theperiodic CSI are transmitted through PUCCH. Specifically, the basestation may inform the UE of the slot-period/offset and the transmissionresource (e.g., OFDM symbol(s) in the slot) of the periodic signalthrough the RRC signal.

When the UE receives a US-PDCCH indicating scheduling for the samesymbol as a symbol for transmitting/receiving a periodic signal/channel(in a periodically configured slot), the UE may determine theconfiguration of the periodic slot according to the most recentlyreceived slot configuration information among the GC-PDCCH(s) andSFI_US-PDCCH received in the monitoring interval. This is because thebase station manages all transmission of periodic signal/channel, andalso manages transmission of scheduling information (e.g., US-PDCCH), sothat the base station scheduler may not schedule to perform differentoperations in the same slot. Therefore, the configuration of theperiodic slot may be determined according to the most recently receivedslot configuration information among the most recently receivedSFI_GC-PDCCH(s) and SFI_US-PDCCH. The UE may determine whether the PDSCHreception (or PUSCH transmission) scheduled by SFI_US-PDCCH is possibleaccording to the determined slot configuration to perform thecorresponding PDSCH reception (or PUSCH transmission). Also, the UE maydetermines whether the periodic signal/channel transmission or receptionis possible to perform transmission/reception or the periodicsignal/channel.

In this case, whether the PDSCH reception (or PUSCH transmission) ispossible (in a slot in which periodic signal transmission and receptionare scheduled) may be determined as follows.

-   -   If the US-PDCCH is received more recently than the GC-PDCCH, the        UE may perform PDSCH reception (or PUSCH transmission) scheduled        by the US-PDCCH (i.e., DCI).    -   If there is a GC-PDCCH received more recently than the US-PDCCH,        when the OFDM symbol(s) to which the PDSCH (or PUSCH) is        allocated by the scheduling information of the US-PDCCH is        configured with DL (or UL) by the slot configuration information        of the GC-PDCCH most recently received within the monitoring        interval, the UE may perform the PDSCH reception (or PUSCH        transmission).    -   If the slot configuration received by the UE when the PDSCH (or        PUSCH) is scheduled through the US-PDCCH is identical to the        slot configuration received by the UE through slot configuration        information of the GC-PDCCH most recently received in the        monitoring interval, the UE may perform the PDSCH reception (or        PUSCH transmission). Otherwise, the UE may not perform the PDSCH        reception (or PUSCH transmission) (e.g., skip/cancel the related        operation).

In addition, as an example of determining whether transmission/receptionof a periodic signal/channel is possible (in a slot which isperiodically configured), if the UL/DL direction of the OFDM symbol(s)to which the transmission/reception of the periodic signal/channel isallocated is identical to the slot configuration received by the UEthrough the slot configuration information of the most recently receivedGC-PDCCH in the monitoring interval or the UL/DL direction of the OFDMsymbol(s) received by the UE through US DCI (i.e., US-PDCCH), the UE mayperform the transmission/reception of the periodic signal/channel (inthe corresponding slot). Otherwise, the UE may not perform thetransmission/reception of the periodic signal/channel (in thecorresponding slot).

FIG. 23 illustrates an operation when a UE configured totransmit/receive periodic signal/channel receives scheduling informationfrom a base station. Referring to FIG. 23 , the UE may be configured totransmit/receive periodic signal/channel in slot n and slot n+3, andreceive a US-PDCCH indicating scheduling information of slot n+3 in slotn+2. In order to determine whether to perform transmission/reception ofa periodic signal/channel in slot n+3 and whether to perform the UEoperation according to scheduling information, the slot configuration ofthe slot n+3 may be determined according to slot configuration based ona US-PDCCH transmitted in the slot closest to the slot n+3 among the GCPDCCHs received in slot n+1 through slot n+3 and the US-PDCCH receivedin slot n+2 or based on the slot configuration information of theGC-PDCCH. In FIG. 23 , the GC-PDCCH (i.e., SFI) of slot n+3 indicatesthe slot configuration closest to the slot n+3. Accordingly, when theGC-PDCCH (i.e., SFI) is received in the slot n+3, the UE may determinethe slot configuration of the slot n+3 according to the slotconfiguration information (e.g., the slot format D) of the GC-PDCCH.

When PDSCH or PUSCH is scheduled in a specific slot (i.e., periodicslot) configured to transmit/receive periodic signal/channel, a specificsignal/channel of some/all of the periodic signals/channels may betransmitted/received without checking slot configuration information forthe corresponding scheduling. In this case, the UE may perform atransmission/reception operation of the specific periodic signal/channelby assuming that the base station properly performs scheduling fortransmission/reception of the corresponding periodic signal/channel sothat collision does not occur. In this case, the specific periodicsignal/channel may include signals having high importance such as asynchronization signal (SS: PSS, SSS)/PBCH block, an RS (e.g., CSI-RS,Phase Tracking RS, Tracking RS), an ACK/NACK transmission channel, an SRtransmission channel, and a beam recovery request (BR), and an SRS. Thespecific periodic signal/channel may include all or a subset of the SS,RS, ACK/NACK transmission channel, SR transmission channel, BRtransmission channel, and SRS. For example, the specific periodicsignal/channel may include ACK/NACK transmission channels. In this case,the ACK/NACK transmission channel may be configured to be received bythe UE without checking the slot configuration information. The PUCCHfor transmitting ACK/NACK may be always allocated to one or more lastOFDM symbols in a slot. For example, the PUCCH (e.g., ACK/NACK) may beallocated to the last one OFDM symbol, the last two OFDM symbols, or 4to 14 OFDM symbols from the last one. The UE may always transmit thePUCCH assuming that OFDM symbols corresponding to the PUCCH areallocated at least UL. In this case, the periodic ACK/NACK refers toACK/NACK indicating whether the reception of the SPS PDSCH configured toreceive periodically is successful. Also, for example, the specificperiodic/signal channel may include an SS, PBCH or SSB transmitted fromthe base station. In this case, the UE may always receive the SS/PBCHblock without checking the slot configuration information.

Override Between SFI and Periodic Signal #3

One of the problems to be solved by the present invention relates to amethod of determining whether to transmit/receive a periodic signalconfigured by RRC to a UE, that is, an operation of a UE for determininga direction of a symbol using information on slot configuration ofSFI_GC-PDCCH and information on slot configuration of SFI_US-PDCCH.

The periodic signal collectively refers to all DL/UL signals configuredto be periodically transmitted by the higher layer (e.g., RRC). In the3GPP NR system, a periodically transmitted UL signal configured in theRRC layer includes a periodic SRS, an SR, a periodic CSI, an SPS-PUSCH,and the like. Further, in the 3GPP NR system, a periodically transmittedDL signal includes a CSI-RS, an SPS-PDSCH, and the like. The SR and theperiodic CSI are transmitted through PUCCH. In addition, a signal whichis configured to the UE through the RRC signal transmitted from the basestation and configured to be periodically received by the UE throughdownlink may include a periodic CSI-RS, a semi-persistent CSI-RS, atracking RS (TRS) or phase tracking RS, SPS-PDSCH or the like.Specifically, the base station may inform the UE of theslot-period/offset and the transmission resource (e.g., OFDM symbol(s)in the slot) of the periodic signal through the RRC signal.

If a symbol in which a signal (i.e., a periodic signal) (e.g., CSI-RS,SPS-PDSCH) configured to be periodically received by the UE in a slot islocated is indicated as a DL symbol through a semi-static DL/ULallocation (i.e., semi-static SFI), the UE may receive the signalconfigured to be periodically received in the corresponding slot. If thesymbol(s) in which the signal configured to be periodically received bythe UE is located in the slot is indicated as Unknown symbol(s) in thesemi-static DL/UL allocation (i.e., semi-static SFI), conditions for theUE to receive the periodic signal in the corresponding slot include: 1)receiving the SFI_GC-PDCCH for the symbol on which the periodic signalis received, and the corresponding SFI_GC-PDCCH indicates the symbol(s)as a DL symbol, or 2) regardless of receiving the SFI_GC-PDCCH, thesymbol(s) in which the signal configured to be periodically received isreceived is indicated as a DL symbol through the SFI_US-PDCCH. In thecase of 1), regardless of whether the SFI_US-PDCCH is detected, the UEmay receive a periodic signal in the corresponding slot. In the case of2), if the symbol(s) in which the signal configured to be periodicallyreceived is received is indicated as a DL symbol through theSFI_US-PDCCH, even if the SFI_GC-PDCCH is not received (that is, theSFI_GC-PDCCH is not detected), the UE may receive a periodic signal inthe corresponding slot. For reference, the UE may determine whether thesymbol in which the signal configured to be periodically received isreceived is a DL symbol through scheduling information of DL data (e.g.,PDSCH) received through the SFI_US-PDCCH. On the contrary, conditionsfor the UE not to receive the signal configured to be periodicallyreceived in the slot may include: 1) receiving the SFI_GC-PDCCH for thesymbol in which the signal configured to be periodically received isreceived, and the corresponding SFI_GC-PDCCH indicates the symbol as anUnknown symbol or a UL symbol, or 2) being failed to receive theSFI_GC-PDCCH, or 3) not receiving information indicating that the symbolin which the signal configured to be periodically received is receivedis a DL symbol from the SFI_US-PDCCH. Considering the override situationbetween the SFI_GC-PDCCH, SFI_US-PDCCH and the periodic signal, the caseof 1) may mean a case where reception of the SFI_US PDCCH has failed,the case of 2) may mean a case where reception of both the SFI_GC-PDCCHand SFI_US-PDCCH has failed, and the case of 3) may mean a case wherereception of the SFI_GC-PDCCH has failed.

A signal which is configured to the UE through the RRC signaltransmitted from the base station and is periodically transmittedthrough uplink includes a periodic SRS, a semi-persistent SRS, and aperiodic PUCCH and SPS-PUSCH for CSI reporting. The periodic PUCCH maybe piggybacked into a PUSCH scheduled by the US-PDCCH. Through the RRCsignal transmitted from the base station, the operation for the UE (oruser) configured to transmit the periodic signal to transmit theperiodic signal is as follows. If a symbol in which a signal configuredto be periodically transmitted by the UE in a slot is located isindicated as a UL symbol through a semi-static DL/UL allocation (i.e.,semi-static SFI), the UE may transmit the signal (e.g., periodic SRS,semi-persistent SRS, CSI, SPS-PUSCH) configured to be periodicallytransmitted in the corresponding slot. In addition, if the symbol inwhich the signal configured to be periodically transmitted by the UE islocated in the slot is indicated as an Unknown symbol in the semi-staticDL/UL allocation (i.e., semi-static SFI), conditions for the UE totransmit the signal configured to be periodically transmitted in thecorresponding slot include: 1) receiving the SFI_GC-PDCCH for the symbolin which the signal configured to be periodically transmitted istransmitted, and the corresponding SFI_GC-PDCCH indicates the symbol asa UL symbol, or 2) regardless of receiving the SFI_GC-PDCCH, the symbolin which the signal configured to be periodically transmitted istransmitted is indicated as a UL symbol through the SFI_US-PDCCH. Forreference, a symbol in which UL data (e.g., PUSCH) is scheduled or a ULcontrol signal (e.g., PUCCH) is scheduled through the SFI_US-PDCCH maybe determined as a UL symbol. In the case of 1), regardless of whetherthe SFI_US-PDCCH is detected, the UE may transmit a periodic signal inthe corresponding slot. In the case of 2), if the symbol(s) in which thesignal configured to be periodically received is received is indicatedas a UL symbol through the SFI_US-PDCCH, even if the SFI_GC-PDCCH is notreceived (that is, the SFI_GC-PDCCH is not detected), the UE maytransmit a periodic signal in the corresponding slot. On the contrary,conditions for the UE not to transmit the signal configured to beperiodically transmitted in the slot may include: 1) receiving theSFI_GC-PDCCH for the symbol in which the signal configured to beperiodically transmitted is transmitted, and the correspondingSFI_GC-PDCCH indicates the symbol as an Unknown symbol or a DL symbol,or 2) being failed to receive the SFI_GC-PDCCH, or 3) not receivinginformation indicating that the symbol in which the signal configured tobe periodically transmitted is transmitted is a UL symbol from theSFI_US-PDCCH or US-PDCCH. Considering the override situation between theSFI_GC-PDCCH, SFI_US-PDCCH and the periodic signal, the case of 1) maymean a case where reception of the SFI_US PDCCH has failed, the case of2) may mean a case where reception of both the SFI_GC-PDCCH andSFI_US-PDCCH has failed, and the case of 3) may mean a case wherereception of the SFI_GC-PDCCH has failed.

Embodiment 3: Overall Operation Related to the Slot Configuration

Hereinafter, as a method of informing configuration information of aslot, a method of determining, by a UE, symbols in a slot asDL/UL/Unknown when there is a semi-static SFI, SFI_GC-PDCCH,SFI_US-PDCCH, or a part thereof will be explained. In the followingdescription, the expression that the SFI is ‘Nothing’ means that thebase station did not transmit the SFI or the UE did not receive it(e.g., PDCCH missing, PDCCH detection failed). In addition, theexpression that the SFI is ‘Anything’ means that some slot configurationinformation is transmitted through the SFI. Unless otherwise specified,SFI=“Anything” includes SFI=“Nothing.” A preferred embodiment of thepresent invention is shown in Table 4.

Referring to Table 4, the UE may determine the format/configuration foreach symbol in the slot as follows. First, the UE may determine theDL/UL/Reserved symbol with the following priority.

-   -   Semi-static SFI >Dynamic SFI from US-PDCCH >Dynamic SFI from        GC-PDCCH

The UE may determine the Unknown symbol with the following priority.

-   -   Dynamic SFI from US-PDCCH >Dynamic SFI from        GC-PDCCH >Semi-static SFI

More specifically, referring to Table 4, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   DL/UL/Reserved symbol configured by semi-static SFI is not        changed.    -   Unknown symbol configured by semi-static SFI or a symbol not        configured by semi-static SFI can be modified by the symbol        configuration of SFI_GC-PDCCH or SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay follow the symbol configuration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay always determine the corresponding symbol by giving priority to theSFI_US-PDCCH.

TABLE 4 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior DL/UL/Reserved Anything AnythingDL/UL/Reserved Unknown Nothing Nothing Unknown Unknown/NothingDL/UL/Unknown Nothing DL/UL/Unknown Unknown/Nothing Anything DL/UL DL/UL

Referring to Table 5, the UE may determine the format/configuration foreach symbol in the slot as follows. First, the priority ofDL/UL/Reserved and the priority of Unknown are configured differently,and the UE may determine the DL/UL/Reserved symbol with the followingpriority. —Semi-static SFI >Dynamic SFI from GC-PDCCH=Dynamic SFI fromUS-PDCCH

In addition, the UE may determine the Unknown symbol with the followingpriority.

-   -   Dynamic SFI from GC-PDCCH=Dynamic SFI from US-PDCCH >Semi-static        SFI

Here, ‘=’ represents the same priority. The priorities between the SFIsindicated by ‘=’ may be determined differently according to the timethat the UE receives the SFI. For example, the recently received SFI mayhave the higher priority.

More specifically, referring to Table 5, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   DL/UL/Reserved symbol configured by semi-static SFI is not        changed.    -   Unknown symbol configured by semi-static SFI or a symbol not        configured by semi-static SFI can be modified by the symbol        configuration of SFI_GC-PDCCH or SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay follow the symbol configuration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay determine the corresponding symbol by giving priority to the mostrecently received one between the SFI_GC-PDCCH and the SFI_PS-PDCCH.When the SFI_GC-PDCCH and the SFI_US-PDCCH are received at the sametime, the UE may always expect a slot format having the same symbolconfiguration. Accordingly, although the SFI_GC-PDCCH and theSFI_US-PDCCH are received at the same time, when different symbolconfigurations are indicated, the UE may determine it as an error case.

TABLE 5 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior DL/UL/Reserved Anything AnythingDL/UL/Reserved Unknown Nothing Nothing Unknown Unknown/NothingDL/UL/Unknown Nothing DL/UL/Unknown Unknown/Nothing Nothing DL/UL DL/ULUnknown/Nothing DL/UL/Unknown Nothing DL/UL/Unknown Unknown/Nothing Samesymbol direction (DL or UL) Follow the same direction (DL or UL)Unknown/Nothing Different symbol direction If Dynamic SFI from GC-PDCCHand Dynamic SFI from UE-specific PDCCH are the same time, Error caseOtherwise, Follow the latest signaling

Referring to Table 6, the UE may determine the format/configuration foreach symbol in the slot as follows. First, the UE may determine theDL/UL/Reserved symbol with the following priority. —Semi-staticSFI >Dynamic SFI from GC-PDCCH >Dynamic SFI from US-PDCCH In addition,the UE may determine the Unknown symbol with the following priority.

-   -   Dynamic SFI from GC-PDCCH >Dynamic SFI from        US-PDCCH >Semi-static SFI

More specifically, referring to Table 6, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   DL/UL/Reserved symbol configured by semi-static SFI is not        changed.    -   Unknown symbol configured by semi-static SFI or a symbol not        configured by semi-static SFI can be modified by the symbol        configuration of SFI_GC-PDCCH or SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay follow the symbol configuration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to an unknown symbol configured bysemi-static SFI or a symbol not configured by semi-static SFI, the UEmay always determine the corresponding symbol by giving priority to theSFI_GC-PDCCH.

TABLE 6 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior DL/UL/Reserved Anything AnythingDL/UL/Reserved Unknown Nothing Nothing Unknown Unknown/NothingDL/UL/Unknown Anything DL/UL/Unknown Unknown/Nothing Nothing DL/UL DL/UL

Next, a case in which the priority of the “Reserved” symbol and thepriority of the DL/UL/Unknown symbol are configured differently will bedescribed. Referring to Table 7, the UE may determine theformat/configuration for each symbol in the slot as follows. First, theUE may determine the Reserved symbol with the following priority.

-   -   Semi-static SFI >Dynamic SFI from GC-PDCCH=Dynamic SFI from        US-PDCCH

In addition, the UE may determine the DL/UL/Unknown symbol with thefollowing priority.

-   -   Dynamic SFI from GC-PDCCH=Dynamic SFI from US-PDCCH >Semi-static        SFI

Here, ‘=’ represents the same priority. The priorities between the SFIsindicated by ‘=’ may be determined differently according to the timethat the UE receives the SFI. For example, the recently received SFI mayhave the higher priority.

More specifically, referring to Table 7, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   DL/UL/Reserved symbol configured by semi-static SFI is not        changed.    -   Unknown symbol configured by semi-static SFI or a symbol not        configured by semi-static SFI can be modified by the symbol        configuration of SFI_GC-PDCCH or SFI_US-PDCCH.    -   Reserved symbol configured by semi-static SFI is always Reserved        symbol.    -   All the symbols except for the Reserved symbol configured by the        semi-static SFI may be changed to a symbol of SFI_GC-PDCCH or        SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may follow the symbolconfiguration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may always determinethe corresponding symbol by giving priority to the SFI_US-PDCCH.

TABLE 7 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior Reserved Anything Anything ReservedDL/UL/Unknown Nothing Nothing DL/UL/Unknown DL/UL/Unknown Nothing DL/ULDL/UL DL/UL/Unknown DL/UL/Unknown Nothing DL/UL/Unknown DL/UL/UnknownSame symbol direction (DL or UL) DL DL/UL/Unknown Different symboldirection If Dynamic SFI from GC-PDCCH and Dynamic SFI from UE-specificPDCCH are the same time, Error case Otherwise Follow the latestsignaling

Referring to Table 8, the UE may determine the format/configuration foreach symbol in the slot as follows. First, the UE may determine thereserved symbol with the following priority. —Semi-static SFI >DynamicSFI from GC-PDCCH=Dynamic SFI from UE-specific PDCCH In addition, the UEmay determine the DL/UL/Unknown symbol with the following priority.

-   -   Dynamic SFI from UE-specific PDCCH >Dynamic SFI from        GC-PDCCH >Semi-static SFI

More specifically, referring to Table 8, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   Reserved symbol configured by semi-static SFI is always Reserved        symbol.    -   All the symbols except for the Reserved symbol configured by the        semi-static SFI may be changed to a symbol of SFI_GC-PDCCH or        SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may follow the symbolconfiguration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may always determinethe corresponding symbol by giving priority to the SFI_US-PDCCH.

TABLE 8 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior Reserved Anything Anything ReservedDL/UL/Unknown Nothing Nothing DL/UL/Unknown DL/UL/Unknown Anything DL/ULDL/UL DL/UL/Unknown DL/UL/Unknown Nothing DL/UL/Unknown

Referring to Table 9, the UE may determine the format/configuration foreach symbol in the slot as follows. First, the UE may determine thereserved symbol with the following priority. —Semi-static SFI >DynamicSFI from GC-PDCCH=Dynamic SFI from UE-specific PDCCH In addition, the UEmay determine the DL/UL/Unknown symbol with the following priority.

-   -   Dynamic SFI from GC-PDCCH >Dynamic SFI from UE-specific        PDCCH >Semi-static SFI

More specifically, referring to Table 9, the UE may determine and definethe format/configuration of symbols in the slot according to the slotconfiguration information and the following symbol determination rule.

-   -   Reserved symbol configured by semi-static SFI is always Reserved        symbol.    -   All the symbols except for the Reserved symbol configured by the        semi-static SFI may be changed to a symbol of SFI_GC-PDCCH or        SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate the same symbolconfiguration with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may follow the symbolconfiguration of SFI_GC-PDCCH and SFI_US-PDCCH.

If the SFI_GC-PDCCH and SFI_US-PDCCH indicate different symbolconfigurations with respect to all the symbols except for the Reservedsymbol configured by the semi-static SFI, the UE may always determinethe corresponding symbol by giving priority to the SFI_GC-PDCCH.

TABLE 9 Dynamic SFI from Dynamic SFI from Semi-static SFI GC-PDCCHUE-specific PDCCH UE behavior Reserved Anything Anything ReservedDL/UL/Unknown Nothing Nothing DL/UL/Unknown DL/UL/Unknown Nothing DL/ULDL/UL DL/UL/Unknown DL/UL/Unknown Anything DL/UL/Unknown

In the methods that the UE determines the format/configuration for eachsymbol in the slot to identify the slot format in Table 4 to Table 9,the UE did not used the direction (e.g., DL, UL or sidelink (SL)) of theperiodic signal/channel which is configured static or semi-static. If aperiodic signal/channel configured to the UE statically orsemi-statically exists, the UE may apply the following UE operations inaddition to Table 4 to Table 9, respectively. —If the direction of thesymbol to which the periodic signal/channel is allocated is identical tothe symbol direction determined by the UE, the UE may transmit/receivethe periodic signal/channel. Otherwise (i.e., the symbol direction isdifferent), the UE may not transmit/receive the periodic signal/channel(e.g., skip transmission/reception operations).

The UE operation for the periodic signal in Table 4 which is a preferredembodiment of the present invention is illustrated in Table 10.

TABLE 10 Dynamic Periodic Dynamic SFI from signal UE behavior SFI fromUE-specific (Configured for periodic Semi-static SFI GC-PDCCH PDCCH byRRC) UE behavior for slot format signals DL/UL/Reserved AnythingAnything DL/UL DL/UL/Reserved receive or transmit Follow Semi-static SFIthe periodic signals Unknown Nothing Nothing DL/UL Unknown cancelperiodic Follow semi-static SFI signals Unknown Unknown Nothing DL/ULUnknwon cancel periodic Follow SFI_GC-PDCCH signals Unknown DL/ULNothing DL/UL DL/UL receive or transmit Follow SFI_GC-PDCCH periodicsignals if direction is right Unknown DL/UL/ DL/UL DL/UL DL/UL receiveor transmit Unknown Follow SFI_US-PDCCH periodic signals if with thehighest priority and direction is right follow SFI_GC-PDCCH

As another example, the UE may determine the configuration informationof the slot, by giving the top priority to the direction of the periodicsignal/channel configured to the UE. That is, the UE may alwaystransmit/receive the periodic signal/channel which is allocatedstatically or semi-statically without changing the direction of theperiodic signal/channel which is statically or semi-statically allocatedto the UE. In addition to the operations of the base station and the UEof Table 4 to Table 9, the symbol determination by the UE according toan embodiment of the present invention is as follows. The configurationof an OFDM symbol that does not overlap with the periodic signal/channelwhich is allocated statically or semi-statically can be found in Table 4to Table 9. The configuration of an OFDM symbol that overlaps with theperiodic signal/channel which is allocated statically or semi-staticallymay be always determined as a direction indicated by the periodicsignal/channel which is allocated statically or semi-staticallyregardless of the UE operations of Table 4 to Table 9. For example, asymbol for transmitting a synchronization signal, PBCH, periodic CSI-RS,and the like may be always regarded as a DL symbol. In addition, asymbol for transmitting a physical random access channel (PRACH) and aperiodic SRS may also be always regarded as a UL symbol. In addition, asymbol for transmitting a periodic PUCCH may also be always regarded asa UL symbol.

The UE may be configured to periodically monitor or receive a controlresource set (CORESET) for receiving the US-PDCCH or GC-PDCCH. In thiscase, if it is determined that the configuration of the symbol in whichthe CORESET is transmitted is DL, the UE may be set to monitor orreceive the CORESET. Additionally, even when the configuration of thesymbol in which the CORESET is transmitted is determined to be Unknownin the semi-static SFI, the UE may be configured to monitor or receivethe CORESET.

Next, a method of determining slot configuration information when a UEmonitors a GC-PDCCH every specific period and the symbol to be monitoredis an UL symbol or an Unknown in the SFI_GC-PDCCH will be described.

For example, when the UE monitors the GC-PDCCH every specific period andthe symbols corresponding to the monitoring CORESET are UL symbols(e.g., informed as UL in the semi-static SFI, informed as UL in thepreviously transmitted SFI_GC-PDCCH, or informed as UL in the previouslytransmitted SFI_US PDCCH), the UE may operate without expecting toreceive the SFI_GC-PDCCH. That is, the UE may determine the slotconfiguration assuming the SFI_GC-PDCCH as ‘Nothing’ in the UEoperations according to Table 4 to Table 9.

As another example, when the UE monitors the GC-PDCCH every specificperiod and the symbols corresponding to the monitoring CORESET are ULsymbols (e.g., informed as UL in the semi-static SFI, informed as UL inthe previously transmitted SFI_GC-PDCCH, or informed as UL in thepreviously transmitted SFI_US PDCCH), the UE may monitor the GC-PDCCH inthe adjacent slot to receive the SFI_GC-PDCCH by assuming that the GCPDCCH is transmitted in the adjacent slot. Preferably, the adjacent slotmay be the most adjacent common-search space in the future among theconfigured common-search spaces. Preferably, the adjacent slot may beindicated by the RRC signal or L1 signal. Referring to FIG. 27(a), theUE may be configured to monitor the SFI_GC-PDCCH every 4 slots. In thiscase, if the CORESET monitoring the SFI_GC-PDCCH in slot n+4 are ULsymbols, the UE may monitor the SFI_GC-PDCCH in slot n+4+k (e.g., n+5)instead of slot n+4. Here, slot n+4+k represents a slot most adjacent toslot n+4 among slots including a DL symbol. Referring to FIG. 27(b), theUE may be configured to monitor the SFI_GC-PDCCH every 4 slots. In thiscase, if the CORESET monitoring the SFI_GC-PDCCH in slot n+4 are ULsymbols, the UE may monitor the SFI_GC-PDCCH in slot n+4-k (e.g., slotn+3) instead of slot n+4. Here, slot n+4-k represents a slot mostadjacent to slot n+4 among slots including a DL symbol.

If the slot to be monitored is changed, the UE may expect SFI_GC-PDCCHof different length. More specifically, the UE may assume that thenumber of slots applied by the slot configuration information of theSFI_GC-PDCCH is the same as the monitoring period. Referring to FIG. 27, if the UE is configured to monitor SFI_GC-PDCCH every 4 slots, theSFI_GC-PDCCH may have slot configuration information of 4 slots. If theslot to be monitored is changed and the UE receives the SFI_GC-PDCCH inthe changed slot, the UE may monitor the GC PDCCH by assuming that slotconfiguration information corresponding to the number of slots from thechanged slot to the next monitored slot is transmitted through theSFI_GC-PDCCH. Referring to FIG. 27(a), since the slot to be monitored ischanged from slot n+4 to slot n+5, the UE may assume that slotconfiguration information for slot n+5, slot n+6 and slot n+7, that is,three slots is transmitted through the GC-PDCCH in slot n+5. Referringto FIG. 27(b), since the slot to be monitored is changed from slot n+4to slot n+3, the UE may assume that slot configuration information forslot n+4, n+5, slot n+6 and slot n+7, that is, four slots is transmittedthrough the GC-PDCCH in slot n+3. In this case, since slot informationfor slot n+3 is expected to be received through SFI_GC-PDCCH in slot n,the SFI_GC-PDCCH transmitted in slot n+3 does not include slotinformation for slot n+3.

The UE may be configured to periodically monitor the SFI_GC-PDCCH. TheUE expects that the SFI_GC-PDCCH will always be transmitted through theGC-PDCCH every monitoring period. When the UE monitors the GC-PDCCHevery monitoring period, but if the UE fails to receive the GC-PDCCH,the UE may assume all the symbols in the slots indicated by theSFI_GC-PDCCH as ‘Unknown’ symbols. Accordingly, the UE may follow the UEoperation when the SFI_GC-PDCCH indicates ‘Unknown’. For example,referring to FIG. 27(a), if the reception of GC-PDCCH in slot n fails,the UE may assume that all the symbols in slot n to slot n+3 are‘Unknown’ symbols.

The UE may be configured to periodically monitor the SFI_GC-PDCCH. Inthis case, the UE may receive, through RRC signaling, information onwhether or not to expect that the GC-PDCCH is transmitted everymonitoring period. Preferably, the information may be indicated by 1 bitin RRC signaling. If the UE is configured to expect that the GC-PDCCH istransmitted every monitoring period, the UE monitors the GC-PDCCH everymonitoring period, and if the UE fails to receive the GC-PDCCH, the UEmay assume all the symbols in the slots indicated by the SFI_GC-PDCCH as‘Unknown’ symbols. Accordingly, the UE may follow the operation of theUE when the SFI_GC-PDCCH indicates ‘Unknown’ (see FIG. 10 ).

On the other hand, if the UE is configured that the GC-PDCCH is notalways transmitted every monitoring period, the UE may monitor theGC-PDCCH every monitoring period, but if the UE fails to receive theGC-PDCCH, the UE may determine the configuration information of all thesymbols in the slots indicated by the SFI_GC-PDCCH as ‘Nothing’.Accordingly, the symbols in the corresponding slots follow thesemi-static DL/UL allocation (i.e., semi-static SFI), symbol directionsof periodically configured signals, symbol directions indicated bySFI_US-PDCCH or US-PDCCH (e.g., DL, UL, unknown, reserved, or guardperiod).

NR supports uplink transmission without UL grant. In this case, the basestation may inform the UE of the resource capable of performing uplinktransmission without the UL grant through the RRC or L1 signal (e.g.,US-PDCCH). Informing the resource through the RRC may be called type-1,and informing that through the L1 signal may be called type-2. The UEmay assume the uplink transmission resource informed by the type-1transmission and the type-2 transmission as follows. The UE may alwaysassume a symbol corresponding to the informed uplink resource regardlessof the two types as a UL symbol. That is, the UL symbol is not changedby other slot configuration information, for example, informationtransmitted in SFI_US-PDCCH. Thus, the UL symbol may be regarded as thesame as what is indicated as the UL symbol in the semi-static DL/ULallocation (i.e., semi-static SFI). As another method, the UE may assumethat a symbol corresponding to an uplink resource indicated by type-1 isalways a UL symbol. Meanwhile, if a symbol corresponding to an uplinkresource indicated by type-2 is located in a resource indicated asUnknown in the semi-static DL/UL allocation, the uplink resource may bechanged to a downlink or Unknown symbol by SFI_GC-PDCCH or SFI_US-PDCCHas same as a symbol in which a periodic signal is configured to betransmit by RRC. That is, the UE may perform the UE operation byregarding the symbols informed by type-1 transmission as UL symbolsinformed by the semi-static SFI, and regarding the symbols informed bytype-2 transmission as symbols in which a periodic signal is configuredto be transmitted/received (see Table 10).

A UE that is not in RRC connected mode (i.e., a UE attempting an initialcell connection or a UE attempting RRC reconnection) may assume a slotconfiguration as follows. First, if the reception of the synchronizationsignal, PBCH is not successful, the UE may assume that all the symbolsof the cell are DL symbols. When the UE receives a PBCH and is allocateda CORESET for monitoring the PDCCH for scheduling the remaining minimumsystem information (RMSI), the UE may assume that the symbols allocatedby the CORESET is downlink and the remaining symbols without theinformation are Unknown symbols. When the UE monitors CORESET andreceives the PDCCH scheduling the RMSI, the UE may determine that thesymbols indicated by the PDCCH are always DL symbols. When the UEreceives the system information through the RMSI or is configured aPRACH resource for random access from the other system informationthereafter, the UE may assume that the PRACH resource is a UL symbol.The UE may maintain the determination until receiving the semi-staticDL/UL allocation information or the semi-static SFI information. The UEattempting RRC reconnection may already have semi-static DL/ULallocation information or semi-static SFI information configured for theUE. Accordingly, the UE attempting RRC reconnection may assume that thesemi-static DL/UL allocation information or the semi-static SFIinformation is valid. The UE attempting RRC reconnection may always givethe priority to the cell-specific new semi-static DL/UL allocationinformation or semi-static SFI information, even if it already hasUE-specifically configured semi-static DL/UL allocation information orsemi-static SFI information.

FIG. 28 is a block diagram illustrating configurations of a userequipment and a base station according to an exemplary embodiment of thepresent invention.

As illustrated, the user equipment 100 according to an embodiment of thepresent invention may include a processor 110, a communication module120, a memory 130, a user interface unit 140, and a display unit 150.

First, the processor 110 may execute various commands or programs andprocess internal data of the user equipment 100. In addition, theprocessor 100 may control an overall operation including each unit ofthe user equipment 100 and control data transmission and receptionbetween the units. In this case, the processor 110 may be configured toperform an operation according to the embodiment described in thepresent invention. For example, the processor 110 may receive slotconfiguration information, determine a slot configuration based on theslot configuration information, and perform communication according tothe determined slot configuration.

Next, the communication module 120 may be an integrated module thatperforms wireless communication using a wireless communication networkand wireless LAN access using a wireless LAN. To this end, thecommunication module 120 may include a plurality of network interfacecards such as the cellular communication interface cards 121 and 122 andthe wireless LAN interface card 123 in an internal or external form.Although the communication module 120 is illustrated as an integratedmodule in the drawing, each network interface card may be independentlyarranged according to a circuit configuration or a purpose, unlike thedrawing.

The cellular communication interface card 121 may transmit and receive awireless signal with at least one of the base station 200, an externaldevice, and a server by using a mobile communication network, and mayprovide the cellular communication service thorough the first frequencyband based on a command of the processor 110. In this case, the wirelesssignal may include various types of data or information such as a voicecall signal, a video call signal, a text/multimedia message, or thelike. The cellular communication interface card 121 may include at leastone NIC module using an LTE-Licensed frequency band. The at least oneNIC module may independently perform cellular communication with atleast one of the base station 200, an external device, and a serveraccording to a cellular communication standard or protocol of afrequency band supported by the corresponding NIC module.

The cellular communication interface card 122 may transmit and receive awireless signal with at least one of the base station 200, an externaldevice, and a server by using a mobile communication network, and mayprovide the cellular communication service through the second frequencyband based on a command of the processor 110. The cellular communicationinterface card 122 may include at least one NIC module using anLTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequencyband may be a band of 2.4 GHz or 5 GHz.

The wireless LAN interface card 123 transmits and receives a wirelesssignal with at least one of the base station 200, an external device,and a server through a wireless LAN connection, and provides a wirelessLAN service by the second frequency band based on a command of theprocessor 110. The wireless LAN interface card 123 may include at leastone NIC module using a wireless LAN frequency band. For example, thewireless LAN frequency band may be an Unlicensed radio band such as aband of 2.4 GHz or 5 GHz. The at least one NIC module may independentlyperform wireless communication with at least one of the base station200, an external device, and a server according to a wireless LANstandard or protocol of a frequency band supported by the correspondingNIC module.

Next, the memory 130 stores a control program used in the user equipment100 and various data according thereto. Such a control program mayinclude a predetermined program necessary for the user equipment 100 toperform wireless communication with at least one of the base station200, an external device, and a server.

Next, the user interface 140 includes various types of input/outputmeans provided in the user equipment 100. That is, the user interface140 may receive a user input using various input means, and theprocessor 110 may control the user equipment 100 based on the receiveduser input. In addition, the user interface 140 may perform an outputbased on a command of the processor 110 using various output means.

Next, the display unit 150 outputs various images on the display screen.The display unit 150 may output various display objects such as acontent executed by the processor 110 or a user interface based on acontrol command of the processor 110.

In addition, the base station 200 according to an embodiment of thepresent invention may include a processor 210, a communication module220, and a memory 230.

First, the processor 210 may execute various commands or programs andprocess internal data of the base station 200. In addition, theprocessor 210 may control an overall operation including each unit ofthe base station 200 and control data transmission and reception betweenthe units. In this case, the processor 210 may be configured to performan operation according to the embodiment described in the presentinvention. For example, the processor 210 may signal slot configurationinformation and perform communication according to the signaled slotconfiguration.

Next, the communication module 220 may be an integrated module thatperforms wireless communication using a wireless communication networkand wireless LAN access using a wireless LAN. To this end, thecommunication module 120 may include a plurality of network interfacecards such as the cellular communication interface cards 221 and 222 andthe wireless LAN interface card 223 in an internal or external form.Although the communication module 220 is illustrated as an integratedmodule in the drawing, each network interface card may be independentlyarranged according to a circuit configuration or a purpose, unlike thedrawing.

The cellular communication interface card 221 may transmit and receive awireless signal with at least one of above-described user equipment 100,an external device, and a server by using a mobile communicationnetwork, and may provide the cellular communication service thorough thefirst frequency band based on a command of the processor 210. In thiscase, the wireless signal may include various types of data orinformation such as a voice call signal, a video call signal, atext/multimedia message, or the like. The cellular communicationinterface card 221 may include at least one NIC module using anLTE-Licensed frequency band. The at least one NIC module mayindependently perform cellular communication with at least one of userequipment 100, an external device, and a server according to a cellularcommunication standard or protocol of a frequency band supported by thecorresponding NIC module.

The cellular communication interface card 222 may transmit and receive awireless signal with at least one of the user equipment 100, an externaldevice, and a server by using a mobile communication network, and mayprovide the cellular communication service through the second frequencyband based on a command of the processor 210. The cellular communicationinterface card 222 may include at least one NIC module using anLTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequencyband may be a band of 2.4 GHz or 5 GHz. According to an embodiment ofthe present invention, the at least one NIC module may independentlyperform cellular communication with at least one of the user equipment100, an external device, and a server according to a cellularcommunication standard or protocol of a frequency band supported by thecorresponding NIC module.

The wireless LAN interface card 223 transmits and receives a wirelesssignal with at least one of the user equipment 100, an external device,and a server through a wireless LAN connection, and provides a wirelessLAN service by the second frequency band based on a command of theprocessor 210. The wireless LAN interface card 223 may include at leastone NIC module using a wireless LAN frequency band. For example, thewireless LAN frequency band may be an Unlicensed radio band such as aband of 2.4 GHz or 5 GHz. The at least one NIC module may independentlyperform wireless communication with at least one of the user equipment100, an external device, and a server according to a wireless LANstandard or protocol of a frequency band supported by the correspondingNIC module.

The user equipment 100 and the base station 200 illustrated in FIG. 28are block diagrams according to an embodiment of the present invention,in which blocks shown separately represent logically distinguishingelements of a device. Therefore, the elements of the above-describeddevice may be mounted in one chip or in a plurality of chips accordingto the design of the device. In addition, some components of the userequipment 100, for example, the user interface 140, the display unit150, and the like, may be selectively provided in the user equipment100. In addition, the user interface 140, the display unit 150, and thelike, may be additionally provided in the base station 200 as necessary.

Although the methods and systems of the present invention have beendescribed in connection with specific embodiments, some or all of theircomponents or operations can be implemented using a computer systemhaving a general purpose hardware architecture.

The foregoing description of the present invention is intended forexemplifications, and it will be understood by those skilled in the artthat the present invention may be easily modified in other specificforms without changing the technical idea and or essential features ofthe present invention. Therefore, it should be understood that theembodiments described above are exemplary in all aspects and notrestrictive. For example, each component described as a single type maybe implemented in a distributed manner, and similarly, componentsdescribed as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claimsrather than the above description, and all changes or modificationsderived from the meaning and scope of the claims and their equivalentsshould be construed as being included in the scope of the presentinvention.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a wireless communication systemand a communication device (e.g., user equipment, base station) for thesame.

1-24. (canceled)
 25. A user equipment used for a wireless communicationsystem, the user equipment comprising: a communication module; and aprocessor, wherein the processor is configured to: receive slot formatinformation through a higher layer signal, and monitor a group common(GC) physical downlink control channel (PDCCH) including a slot formatindicator (SFI) and/or a user specific (US) PDCCH, for a symbol setconfigured as flexible by the slot format information in a slot, areception of a downlink signal is selectively performed at least basedon the GC PDCCH and/or the US PDCCH.